This volume enables readers to interpret and predict the effective mechanical properties of existing and emerging composites through modeling and design. The book addresses that materials and structures with small-scale dimensions do not behave in the same manner as their bulk counterparts. Once the dimensions of the materials are reduced to the micron and sub-micron range, their properties are subject to significant change. Thus, mechanical properties will be varied and will depend on the sample size. In the meantime, due to the large surface-to-volume ration of small structures, deformation mechanisms are subject to change. This volume integrates various approaches in micromechanics and nanomechanics into a unified mathematical framework, complete with coverage of both linear and nonlinear behaviors. It weaves together the basic concepts, mathematical fundamentals, and formulations of micromechanics and nanomechanics into a systemic approach for understanding and modeling the effective material behavior of composite materials. While providing information on recent developments in the mathematical framework of micro- and nanomechanics, the volume addresses highly localized phenomena and a number of interesting applications. It also illustrates application of micromechanical and nanomechanical theory to design novel engineering materials.