Many man-made materials and naturally occurring substances are aggregates of crystals, or polycrystals, with a non-random distribution of orientations. In such textured polycrystals, many macroscopic physical properties are anisotropic, i.e. they depend on direction. This book is about the measurement and analysis of textures, the prediction of polycrystal properties from measured textures and known single crystal properties, and the prediction of the development of texture and the ensuing anisotropic properties during elastic and plastic deformation. It also gives an overview of observed textures in metals, ceramics and rocks. There is a balance between theoretical concepts and experimental techniques. The book addresses several issues. Part I provides tools and describes methods to obtain quantitative data on textures of polycrystals. It should be of interest to experimentalists. Part II emphasizes modeling of deformation and incorporates theoretical concepts of mechanics. Part III illustrates successful applications in engineering and earth sciences.