In terms of design, multifunctional requirements are becoming the rule. While previous decades were driven by the development of new materials, this new engineering approach calls for the development of 'tailored materials'. Very often, contradictory requirements cannot be met by a single material. Fortunately, various innovative strategies are possible -associating different materials, playing with materials architectures (such as foams and truss lattices), or developing microstructural gradients. While these strategies open a whole new range of materials and properties, where structural requirements and functional properties can be combined, they also reveal additional challenges. New processes must be implemented. Appropriate constitutive equations must be developed. Interfaces must be engineered. And bioinspired hierarchical structures must be developed and modeled, to name just a few. This book brings together researchers to review recent advances and address the list of challenges. Topics include: basic concepts in architecture materials; cellular and fibrous materials; processing challenges; towards structures and multifunctional materials.