This monograph is devoted to a detailed treatment of the nonlinear optical properties of liquid crystals. The basic concepts of director optical reorientation and thermal nonlinearities are presented using a fundamental mathematical approach and an experimental demonstration of the main phenomena. The presentation is self-consistent and tutorial, although the subject matter is a of current research interest. The last part of the book deals with more recent results on new composite materials: polymer dispersed liquid crystals. A general presentation of the optical properties is given and the...