Book excerpt: There has recently been a rapid growth of activity in nonlinear optics. Effects such as frequency doubling, stimulated Raman scattering, phase conjugation and solitons are of great interest both for their fundamental properties and their many important applications in science and engineering. It is mainly these applications - especially in telecommunications and information processing - that have stimulated the recent surge of activity. This book is a self contained account of the most important principles of nonlinear optics. Assuming only a familiarity with basic mathematics, the fundamentals of nonlinear optics are fully developed from basic concepts. The essential quantum mechanical apparatus is introduced and explained. In later chapters the underlying ideas are illustrated by discussing particular experimental configurations and materials. This book will be an invaluable introduction to the field for beginning graduates in physics or engineering, and will provide an excellent overview and reference work for active researchers in the field.