Current world technologies and environments rely in large measure on the development of new structural materials with high strength and durability, light weight, low cost, and complete recyclability. Such materials may be derived synthetically, but nature has evolved efficient strategies leading to low-weight structural materials with exceptional strength, durability and other unique properties. The ability to mimic these structures and understand their structure-mechanical property relationships should lead to similarly behavior in both biomedical and materials arenas and is the focus of this book. Resultant materials offer a new combination of low-weight, high-strength/durability and multifunctionality for applications in automotive, energy, shipbuilding, defense, and civil and aerospace engineering. Development of advanced bio- and tissue-engineered materials are also crucial in instances where biological materials need to be replaced, repaired or regenerated. Topics include: structure-function relationships in biomineralized tissues; structure-property relationships in biomimetic composites; reverse deformation and fracture mechanics of biological composites; biomaterials in tissue engineering and high-resolution imaging techniques for characterizing organic-inorganic composites.