The book gives an overview of actual developments in nonlinear photorefractive optics and is intended for scientists working in the field of optics or nonlinear physics. It is meant as an introduction to actual exciting discoveries in this area, with special emphasize on transverse effects such as spatial soliton formation and interaction, spontaneous pattern formation, and pattern competition in active feedback systems. In all these areas, different aspects of potential applications, such as wave guiding in adaptive photorefractive solitons and techniques for pattern control for information processing, are described. Experimental realizations demonstrate the variety of photorefractive patterns, and different two-dimensional simulations prove the experimental observations.