Nearly a decade aga a general review article on the evaluation of optical radia tion hazards was published in Applied Optics (Sliney and Freasier, 1973). This arti cle received many favorable comments but also prompted many inquiries regarding specific optical hazard problems. From this it became evident that a monograph rather than a supplemental and expanded article was needed to fill this literature gap relating to laser and optical radiation hazards. The present work is designed to fill that gap, and is structured to permit either classroom or self-study use. Much of the material in this book was developed in eonnection with short courses on laser safety and radiometry in which we have participated, as weIl as from our previous articles. In particular, the sequenee of chapters is based upon the experiences which we have had in lecturing in courses with different schedules. One of the great difficulties in developing a text of this nature is that a broad, multidisciplinary background must be included in order that the reader can comprehend all of the subjeet matter readily. For this reason, the material presented on anatomy and physiology is orien ted toward the engineer or physical scientist, while the review material on basic optical physics is intended more for the physician or life scientist.