This book is intended for upperclass college students as an introduction to the growing field of coherent optics and to the increasing number of its applications, and also for those versed in other fields who wish to gain per spective and insight without detailed calculations. It is an outgrowth of the author's Science Study Series book Lasers and HolographY. * Besides being an updated and expanded version of that book, it includes discussions of numerous recent applications. It differs in its slightly higher analytical level and in the inclusion oflarge numbers of references, which enable the reader to obtain further information on subjects of interest to him. The level was selected to match the capabilities of students in their middle college years so as to permit them to make an early assessment of possible career interests in any of the many interdisciplinary fields now embracing the technologies of modern optics. It is hoped that the book can be used (as has occurred rather extensively with another of the author's Science Study Series books, Sound Waves and Light Wavest) as an auxiliary reading assignment for students in various disciplines. The author strongly believes that the promise of continued growth in this field, as evidenced by the extensive participation in technology develop ments by industry, both within the U. S. and abroad, identifies the subject as * Doubleday, 1969 (hard cover and paperback).