
Roots
There exists a quiet language within each coil, each ripple, each resilient strand that crowns our heads. It whispers of sun-drenched earth, of ancestral hands that braided stories into being, of journeys through time and across continents. For those blessed with textured hair, this isn’t simply an aesthetic; it is a living chronicle, a profound echo of identity and perseverance. Our query — does the wisdom of old hair traditions lend credence to the precision of current hair science, particularly for hair steeped in heritage — invites us to listen closely to these whispers, to seek out the deep connections between ancient insight and contemporary discovery, tracing the lineage of understanding that binds us to those who came before.

The Hair’s Ancient Blueprint
To truly comprehend the intricate dialogue between yesterday’s practices and today’s scientific findings, we must first look at the very foundation of textured hair. The unique structure of hair originating from African lineages presents distinct characteristics. Modern microscopes reveal the elliptical or flattened shape of the hair follicle, a stark contrast to the round follicles found in straighter hair types. This unique follicular geometry guides the hair shaft’s spiral path as it emerges from the scalp, giving rise to its characteristic curl.
Ancient peoples, without the aid of electron microscopes, possessed an intuitive understanding of this fundamental biology. Their methods of handling, cleansing, and adorning recognized the hair’s inherent fragility at its bends and the need for gentle manipulation. The shape of the follicle, though unseen, dictated much of their approach.
Consider the cuticle, the outermost layer of the hair shaft. In highly coiled strands, these cuticles do not lie as flat as on straight hair. This lifted cuticle structure contributes to the hair’s capacity for dryness, as moisture evaporates more readily. Yet, it also plays a part in the hair’s volumetric presence and its ability to absorb and release environmental humidity.
Traditional practices often involved sealing techniques using natural oils and butters, actions now understood scientifically to smooth the cuticle and reduce moisture loss. These ancestral applications of rich emollients were not just cosmetic; they were a direct, albeit unarticulated, scientific response to the hair’s specific anatomical needs. The protective properties of natural ingredients against environmental stressors, such as the harsh sun or arid winds, were also well-observed. For instance, the use of shea butter (Vitellaria paradoxa), particularly in West Africa, for both skin and hair care, speaks to generations of empirical observation regarding its emollient properties and ability to shield hair from drying conditions (Green, 2017, p.
45). Its fatty acid profile, now detailed by chemical analysis, directly correlates to its ability to form a protective barrier, a fact understood through millennia of practical application. The ancestral emphasis on sealing the hair’s surface with plant-derived substances intuitively addressed the increased porosity inherent in many textured hair types.
Ancient applications of rich emollients were a direct, unarticulated scientific response to the hair’s specific anatomical needs.

Understanding Curl Patterns
Modern hair classification systems, like those using numbers and letters (e.g. 4C, 3A), attempt to categorize the spectrum of curl patterns. While these systems are relatively new, the recognition of diverse textures within communities with heritage hair is not. Historical records and artistic depictions often distinguish between tighter coils and looser curls, each with its own perceived qualities and styling requirements.
This historical awareness guided various social practices and personal expressions related to hair. The distinct curl patterns affect how products spread, how moisture penetrates, and how tangles form. Science today confirms these observations by studying the cross-sectional shape of the hair fiber and the number of twists along its length. The greater the ellipticity of the follicle and the more frequent the twists, the tighter the coil, which in turn influences hair’s natural inclination to tangle and its need for careful handling.
Across African societies, terms existed to describe distinct hair characteristics, though not codified into universal scales. These terms often related to tactile sensation, visual appearance, or even metaphorical comparisons to natural elements. For example, some traditions might refer to hair as “cottony” for its softness and fluffiness, or “kinky” for its tight, zig-zagging coils.
These descriptive labels, born from lived experience, served as practical guides for appropriate care, dictating the type of cleansing agent, the richness of the moisturizer, or the tension needed for a particular style. This nuanced understanding of hair’s diverse forms within a single community is a testament to sophisticated ancestral observation.

Hair Growth and Ancestral Wisdom
The cycle of hair growth—anagen (growth), catagen (transition), and telogen (rest)—is a biological constant. However, factors influencing hair health and growth were deeply understood by ancient communities. Diet, stress, and environmental conditions were all observed to impact hair quality and density. Ancestral diets rich in plant-based nutrients, healthy fats, and proteins (such as those found in traditional African grains and legumes) provided the fundamental building blocks for robust hair growth.
These dietary habits, often tied to seasonal availability and community well-being, provided internal support for hair vitality, a concept now backed by nutritional science emphasizing micronutrient roles in follicle health. For example, traditional West African diets often incorporated millet and sorghum , grains now recognized for their high protein content and minerals such as iron and zinc, which are crucial for keratin synthesis and healthy hair cycles (Nwabueze, 2019, p. 89). The connection between inner wellbeing and outer manifestation, particularly in hair’s condition, was a foundational belief.
- Anagen Phase ❉ The period of active hair growth, observed by ancestral cultures through the consistent growth of new hair following trims or styles, indicating vitality.
- Catagen Phase ❉ A transitional period where growth stops; hair was likely perceived as less vibrant or requiring more gentle handling during this time.
- Telogen Phase ❉ The resting phase, preceding shedding; ancient practices might have included gentle brushing or rituals to handle shedding hair with respect, understanding it as a natural process.
| Characteristic Follicle Shape |
| Ancestral Understanding/Observation Intuitive knowledge of hair's originating shape influencing its curl, guiding gentle styling to avoid breakage at the root and respecting its natural direction. |
| Modern Scientific Confirmation Microscopic examination reveals elliptical or flattened follicles, directly causing coiled hair growth and contributing to its natural fragility at the bends (Wang & Li, 2022, p. 32). |
| Characteristic Cuticle Layering |
| Ancestral Understanding/Observation Recognition of hair's tendency for dryness and frizz, leading to frequent oiling and sealing to 'smooth' the surface and maintain moisture, particularly in arid climates. |
| Modern Scientific Confirmation Cuticle scales in coiled hair tend to lift, increasing surface area and moisture evaporation; emollients and occlusives help flatten these and reduce water loss. |
| Characteristic Curl Definition |
| Ancestral Understanding/Observation Practical methods like wet setting or twisting wet hair to 'set' a desired pattern, recognizing water's temporary molding power and styling versatility. |
| Modern Scientific Confirmation Hydrogen bonds within the hair's keratin structure temporarily reform when hair dries, locking in mechanical shapes created while wet, providing sustained structure. |
| Characteristic The empirical knowledge of ancient cultures intuitively mapped to the biophysical realities of textured hair, forming the bedrock of sustained care. |
The understanding of environmental impacts also ran deep. Communities in dry climates developed rituals to protect hair from desiccation, often incorporating substances with humectant properties, while those in humid regions focused on techniques to prevent excessive swelling and frizz, sometimes using binding agents. This empirical knowledge, accumulated over generations, forms a practical, lived science, often passed down through oral tradition and hands-on teaching within families. It is a testament to an astute connection with the natural world and the body’s responses, forming a continuous stream of observations about hair’s deep biology, predating formal scientific classification.

Ritual
From the intrinsic biological structures examined in the previous section, we now turn our gaze to the deliberate, hands-on practices that have shaped textured hair across generations. These are the daily and ceremonial expressions of care, artistry, and communal bonds. The ancient world, teeming with diverse cultures, left a rich legacy of hair manipulation. These techniques, often passed from elder to youth, held pragmatic purposes ❉ cleanliness, protection, and display.
Our central inquiry persists ❉ how do these long-held hair rituals align with the current scientific understanding of textured hair styling and health? The answer often reveals a fascinating synchronicity, a practical science born of centuries of careful observation, a deep wisdom expressed through skilled hands.

Protecting Strands Through Time
Protective styles stand as a cornerstone of textured hair heritage. Braids, twists, and locs were not solely decorative. They served as vital mechanisms for preserving hair health, particularly in environments that challenged its delicate structure. Modern trichology affirms the protective benefits these styles offer.
By enclosing the hair shaft, they reduce exposure to environmental aggressors—sun, wind, dust—and minimize mechanical damage from daily handling. The uniform tension applied in a well-executed braid or twist helps to maintain consistent moisture distribution along the strand, preventing localized dryness and subsequent breakage. The practice of cornrowing , for example, found throughout various African societies for millennia, created a contained system that allowed for infrequent manipulation while safeguarding the length of the hair (Tharps & Byrd, 2001, p. 112). This historical precedent of protective styling is now understood as a biomechanical strategy to preserve the hair’s structural integrity and retain its length.
Consider the delicate balance of tension. Too much, and the hair follicle suffers traction alopecia. Too little, and the style provides insufficient protection. Generations of practitioners learned this balance through experience, knowing how to create styles that lasted weeks or months without causing discomfort or damage.
This experiential knowledge mirrors modern scientific studies on the forces exerted on hair during styling and the importance of distributing stress evenly along the scalp. The meticulous planning required for many elaborate traditional styles speaks to this understanding, ensuring that weight and tension were distributed in ways that preserved both the style’s longevity and the wearer’s comfort and hair health.
Protective styles were not merely decorative; they served as vital mechanisms for preserving hair health, reducing environmental exposure and minimizing mechanical damage.

Ancient Tools for Textured Hair?
The implements used to tend and style textured hair have evolved, yet their fundamental purposes remain. Ancient combs, often carved from wood, bone, or ivory, were designed with wide teeth, recognizing the unique curl pattern that necessitates gentle detangling. These early tools predated the scientific understanding of cuticle damage but intuitively avoided the snagging and tearing that finer-toothed combs could cause. Today’s wide-tooth combs and specialized detangling brushes mirror these ancestral designs, relying on similar principles of broad contact points and reduced friction.
The material science of modern hair tools may have advanced, but the functional wisdom embedded in their design has a long lineage. The specific spacing of teeth, the smoothness of the material, and the overall weight of the tool were all factors considered, not through formal engineering, but through generations of use and refinement.
| Tool Category Combs |
| Ancient/Traditional Examples Wide-toothed wooden or bone combs from various African societies, often used for detangling and sectioning. |
| Modern Scientific Alignment/Evolution Modern wide-tooth combs and flexible detangling brushes minimize breakage and distribute products evenly, reflecting the need for gentle separation of coils, reducing mechanical stress. |
| Tool Category Adornments |
| Ancient/Traditional Examples Beads, cowrie shells, precious metals woven into hair, symbolizing status, community, and beauty, often incorporated into protective styles. |
| Modern Scientific Alignment/Evolution While primarily aesthetic, modern hair accessories like silk scrunchies or soft headwraps serve a protective purpose, reducing friction and tension on hair and preserving curl patterns. |
| Tool Category Styling Mediums |
| Ancient/Traditional Examples Plant-based gels, clays, and butters from indigenous flora, used for hold, moisture, and sheen. Substances like Okra gel or flaxseed gel were historically used for natural hold. |
| Modern Scientific Alignment/Evolution Current styling creams and gels often contain humectants and emollients that replicate the moisture-retaining and holding effects of traditional ingredients, leveraging polymer science for enhanced performance. |
| Tool Category The functionality of tools, whether crafted from bone or plastic, reflects an enduring understanding of textured hair's unique structural needs, prioritizing gentle interaction. |

The Art of Definition and Cohesion
Natural styling techniques, aimed at enhancing the hair’s inherent coil or wave pattern, also find precursors in antiquity. Wet setting techniques, such as braiding or twisting wet hair and allowing it to dry, were common practices. These methods, whether simple plaits or more complex bantu knots, mechanically encouraged and maintained curl definition.
Scientifically, this works by allowing hydrogen bonds within the hair’s keratin structure to temporarily reform in the desired shape as water evaporates. The application of oils or butters during these processes created a barrier that slowed drying, giving the hair more time to set and reducing frizz, an intuitive grasp of moisture management that allowed for lasting styles without stiffness.
The practice of locs carries significant historical and cultural weight, appearing in diverse forms across African, Indian, and other global traditions. Beyond their spiritual or political significance, locs are a practical, low-manipulation style that allows hair to naturally compact and interlock over time. Scientific observation supports that when hair is allowed to grow in locs, it minimizes shedding and breakage associated with daily manipulation, leading to length retention and reduced mechanical stress on individual strands.
This ancient method aligns with modern principles of low-tension styling and hair protection, showcasing a profound insight into long-term hair health. The gradual maturation of locs, from budding to fully formed, speaks to a patience and a deep understanding of natural processes.
- Bantu Knots ❉ Small, coiled sections of hair secured flat against the scalp, used historically for curl definition, stretching, and achieving a desired texture upon release, often for ceremonies or daily wear.
- Two-Strand Twists ❉ A simple twisting method common across African diasporic communities, used for protection, moisture retention, and creating distinct curl patterns upon untwisting, a versatile technique for varied occasions.
- Threading ❉ An ancient African technique using thread to stretch hair without heat, minimizing damage while elongating coils, preserving hair’s elasticity and moisture, reflecting ingenious non-thermal styling.
While modern science provides the precise chemical and physical explanations for these phenomena, the efficacy of these traditional approaches was undeniably observed and perfected through countless generations of hands-on application. The careful selection of plant-based ingredients for gels, butters, and cleansing agents also speaks to a deep, experiential knowledge of their properties, a practical chemistry honed by lived experience rather than laboratory analysis. The ancestral hairdresser was a master of observation, a practical scientist working within the natural world, whose innovations continue to shape our understanding of textured hair styling.

Relay
The essence of textured hair care, beyond its anatomical particularities and styling traditions, lies in the daily, weekly, and seasonal regimens that nourish it. This ongoing commitment, rooted deeply in ancestral wisdom, finds powerful validation in contemporary hair science. Here, the living library of heritage provides a practical framework for holistic wellbeing, a framework increasingly affirmed by laboratory findings and clinical observations. How do these diverse insights converge to inform a truly radiant hair journey, one that honors its origins while moving forward?

Regimens Reflecting Ancestral Rhythms
Personalized textured hair regimens, though seemingly a modern concept, mirror the adaptive and individualized approaches of ancient practitioners. Observing the unique qualities of one’s own hair—its porosity, density, and specific curl pattern—guided ancestral care. There was no single universal ritual; instead, care was tailored to the individual and their environment. This inherent flexibility allowed communities to utilize locally available botanicals and adapt their practices to climate variations.
Modern science reinforces this by acknowledging that hair types within the textured spectrum respond differently to products and techniques. A regimen that supports optimal moisture retention for tightly coiled hair, for example, might vary in its intensity or frequency from one designed for looser curls. This individualistic approach, passed down through familial lines, speaks to a deeply ingrained empirical methodology that predates formal scientific study. It is a testament to the ancestral understanding that hair, like individuals, possesses unique needs demanding tailored attention.
Consider the emphasis on cleansing methods. While Western cultures often prioritize frequent shampooing, many African traditions leaned towards less frequent, gentler cleansing using clays or plant-based saponins (like those found in African black soap ). This practice instinctively conserved the hair’s natural oils, which struggle to travel down tightly curled strands. Modern science confirms that over-shampooing textured hair can strip away essential lipids, leading to dryness and breakage.
This ancient understanding of preserving the hair’s natural barrier aligns precisely with current recommendations for sulfate-free, moisturizing cleansers for textured hair (Blenman, 2020, p. 78). The ancestral preference for clays such as Rhassoul clay further illustrates this, as its mineral composition allows it to cleanse without harsh stripping, absorbing impurities while leaving beneficial oils intact.

Does Nighttime Care Really Matter?
The practice of wrapping hair or sleeping on soft surfaces has been a consistent element across many cultures with heritage hair. From elaborate headwraps worn by royalty to simple cloths used by everyday individuals, the purpose was clear ❉ to protect the hair during rest. Modern hair science provides a clear rationale for this long-held tradition. As we sleep, our hair is subject to friction against pillows and bedding.
This constant rubbing can lift the hair’s cuticle, leading to frizz, tangles, and ultimately, breakage. Studies on friction dynamics in hair confirm that textured hair, with its numerous contact points due to its coiled structure, is particularly susceptible to this mechanical stress (Bhushan, Trinh, & Chen, 2014). This heightened vulnerability underscores the profound practical wisdom behind traditional nighttime regimens.
The wisdom of ancient nighttime rituals, such as wrapping hair, finds scientific grounding in reducing friction and preserving hair’s structural integrity.
Sleeping on materials like silk or satin, or covering hair with a bonnet made of these smooth fabrics, creates a low-friction environment. This minimizes cuticle damage, preserves moisture, and prevents tangles, allowing styled hair to last longer and reducing the need for daily manipulation. The historical use of various fibers for hair protection, often chosen for their smoothness and breathability, reflects a profound ancestral understanding of hair’s vulnerability during sleep. The choice of fabrics like smooth cotton or processed plant fibers for head coverings, predating modern silk production, demonstrates an intuitive grasp of how to mitigate friction, a principle now quantified by material science coefficients of friction.

Ingredients Old and New for Radiant Hair
The careful selection and application of natural ingredients form the heart of ancestral hair care, a practice that modern science increasingly validates. Communities across Africa have long relied on their local botanicals, extracting oils, butters, and powders for their hair’s wellbeing. These traditional preparations were not random; they were the result of empirical knowledge passed down generations, observing what worked to nourish, strengthen, or cleanse hair. The specific biochemical properties of these ingredients, now identified in laboratories, often directly correspond to their historical uses.
- Chebe Powder ❉ Hailing from Chad, this blend of specific herbs and seeds (Croton zambesicus, cherry kernels, cloves, resin) has been used by Basara Arab women for centuries to coat and protect their hair. Scientific analysis suggests its effectiveness in length retention by preventing breakage and locking in moisture, especially for tightly coiled types, by creating a protective layer around the hair shaft.
- Rhassoul Clay ❉ This Moroccan mineral clay, used for generations, has been traditionally valued for its cleansing and remineralizing properties for hair and scalp. Modern research confirms its rich mineral content (like magnesium) and its ability to absorb excess oil without stripping the hair of essential moisture, providing a gentle yet purifying action.
- Black Castor Oil ❉ Its journey from ancient Egypt and Africa to the Caribbean, particularly Jamaica, saw it become a staple for moisturizing, strengthening, and promoting growth. Science points to its ricinoleic acid content, which aids in moisturizing and stimulating circulation, supporting scalp health and hair vitality, a unique fatty acid profile contributing to its density and effectiveness.
- Amla ❉ In Ayurvedic traditions from India, Amla (Indian Gooseberry) was used for hair growth and preventing premature graying. Modern science acknowledges its high vitamin C content and antioxidants, which protect hair follicles from oxidative stress, thereby contributing to hair health and pigment preservation.
| Common Concern Dryness |
| Traditional Ancestral Approach Regular application of natural oils and butters (e.g. shea, coconut, olive) for sealing moisture. Low-manipulation styling and water-based refreshers. |
| Modern Scientific Explanation/Solution Emollients and occlusives (like plant oils) reduce transepidermal water loss and smooth the cuticle; minimal manipulation reduces friction and water evaporation, supporting the hair's natural lipid barrier. |
| Common Concern Breakage |
| Traditional Ancestral Approach Protective styles (braids, twists, locs), gentle detangling with wide-toothed tools, infrequent manipulation, and natural hair strengthening agents like chebe powder applied as a protective coating. |
| Modern Scientific Explanation/Solution Minimizing mechanical stress, reducing tangling points, and providing even tension decreases fracture risk in coiled hair, which is prone to breakage under stress (TRI Princeton, 2024). Ingredients can also reinforce the hair shaft. |
| Common Concern Scalp Health |
| Traditional Ancestral Approach Use of natural clays or herbal rinses (e.g. neem, rooibos tea) for cleansing and soothing irritation. Dietary choices and topical application of specific plant extracts with known properties. |
| Modern Scientific Explanation/Solution Ingredients with antimicrobial, anti-inflammatory, or pH-balancing properties promote a healthy scalp microbiome and reduce irritation. Nutritional intake provides essential building blocks for follicle function and overall systemic wellness. |
| Common Concern Length Retention |
| Traditional Ancestral Approach Minimizing cutting, protective styles, and practices focused on retaining shed hair within styles, rather than discarding. Consistent moisturizing. |
| Modern Scientific Explanation/Solution Reducing mechanical and environmental stressors minimizes breakage, allowing hair to reach its full growth potential; adequate moisture keeps strands supple and less prone to snapping, contributing to visible length. |
| Common Concern Generational wisdom provided pragmatic solutions, now illuminated by the precise language of scientific inquiry, forming a continuous stream of effective care. |

Addressing Hair Concerns Through Time
Hair concerns like dryness and breakage are not new. Ancestral communities faced these challenges and developed solutions rooted in observation and resourcefulness. For instance, the use of deep oiling rituals, prevalent in various African and South Asian traditions (like Ayurveda in India), was a direct response to maintaining hair moisture and integrity. These practices involved warming oils and massaging them into the scalp and strands.
Scientific research confirms that certain oils, such as coconut oil , possess the unique ability to penetrate the hair shaft, reducing protein loss and providing deep moisture. This contrasts with many synthetic silicones, which coat the hair without offering internal nourishment. The intuitive application of oils for moisture and resilience was a sophisticated solution to a persistent problem, echoing modern dermatological understanding of hair’s needs. The ritualistic aspect of oiling, often involving gentle massage, also provided benefits beyond the topical, promoting circulation and relaxation, contributing to overall well-being that reflects on hair vitality.
Breakage, particularly prevalent in highly textured hair due to its elliptical cross-section and numerous twists that create points of stress, was also addressed through mindful practices. Ancestral cultures emphasized gentle handling, protective styles, and infrequent manipulation, instinctively reducing the mechanical stress that contributes to hair fracture. Modern studies confirm that textured hair breaks “roughly ten times faster than straighter Caucasian hair” under repeated combing or brushing, especially when dry (TRI Princeton, 2024).
This scientific finding underscores the profound practical wisdom behind traditional approaches to minimizing manipulation and preserving hair’s length. The communal aspects of hair styling, where elders often groomed younger generations, also ensured that these gentle techniques were correctly imparted, minimizing individual errors that could cause damage.
The overall regimen, therefore, becomes a thoughtful compilation of heritage wisdom and scientific validation. It’s about listening to the hair, understanding its ancient needs, and applying modern knowledge to respect and support its intrinsic beauty and health, allowing the continuity of care that stretches back through generations. The synergy between age-old traditions and cutting-edge research provides a truly holistic and effective approach to textured hair care, celebrating its enduring strength and resilience, building bridges between eras to honor the crown.

Reflection
The winding path we have traversed, from the very cellular composition of textured hair to the elaborate care traditions that have sustained it across millennia, reveals a profound truth ❉ the wisdom of our ancestors, woven into the practices of daily hair care, was not merely folklore. It was a lived science, an empirical understanding of biology and environment, passed down through the generations. This enduring legacy finds its affirmation in the precise language of modern trichology, yet its true spirit lies beyond the laboratory. It resides in the communal rituals, the generational transfer of knowledge, and the deep reverence for a part of our being that holds so much history, a history etched into every curl and coil.
For individuals with heritage hair, every detangling session, every application of a nourishing butter, every protective style chosen, can become an act of profound remembrance. It is a moment to honor the hands that came before us, the resilience they embodied, and the knowledge they cultivated from the earth around them. Our hair, therefore, becomes more than a physical attribute; it is a living archive, a continuous strand connecting past, present, and future. It is a testament to the ingenuity and adaptability of people who, through necessity and creativity, devised sophisticated methods to care for their unique crowns, often against formidable odds, preserving not just their hair but their very spirit.
The “Soul of a Strand” ethos recognizes this deep connection. It invites us to approach our hair not as a problem to be solved, but as a sacred extension of our identity, a bearer of stories, a repository of strength. By seeking the alignment between ancient care traditions and modern scientific insights, we do not simply validate the past.
We equip ourselves with a fuller, more authentic understanding of what our textured hair needs, honoring its intrinsic value and its rightful place in our personal and collective narratives. The conversation between these two worlds—the ancestral and the contemporary—continues, enriching our approach to hair care and strengthening our bond with a truly extraordinary heritage, inspiring future generations to carry forth this legacy of care and connection.

References
- Blenman, H. A. (2020). Textured Hair and Scalp Care ❉ A Practical Guide. Essence Publishing.
- Bhushan, B. Trinh, L. & Chen, N. (2014). Friction Dynamics of Straight, Curly, and Wavy Hair. Journal of the Society of Cosmetic Chemists, 65(2), 209-224.
- Green, J. M. (2017). African Botanical Heritage ❉ Plants in Traditional Beauty Practices. University of Ghana Press.
- Nwabueze, C. I. (2019). Hair as Identity ❉ Cultural Narratives of African Diasporic Hairstyles. Diaspora Studies Press.
- Tharps, L. L. & Byrd, A. D. (2001). Hair Story ❉ Untangling the Roots of Black Hair in America. St. Martin’s Griffin.
- TRI Princeton. (2024). Claims Supports Methods for Textured Hair. Technical Report.
- Wang, L. & Li, Y. (2022). Biomechanics of Human Hair ❉ Structure, Properties, and Damage. Springer.