This work is a comprehensive volume on nonlinear dynamics and chaos in optical systems. It summarizes nonlinear dynamic problems in optical complex systems possessing large degrees of freedom, systematically featuring our original experimental results and their theoretical treatments. This book focuses on nonlinear dynamics and cooperative functions in realistic optical complex systems, such as multimode lasers, laser array, coupled nonlinear-element systems, and their applications to optical processing. It should be helpful for graduate students majoring in optical and laser physics, and the generic nature of complex systems described in this book may be of use to researchers in the field of nonlinear dynamics covering different academic areas including applied mathematics, hydrodynamics, celestial mechanics, chemistry, biology and economics.