Book excerpt: This book is based on a series of lectures given at a Summer School held in Mar del Plata, Argentina, during the Winter (Southamerican) of 1988. A number of world renowned researchers have produced comprehensive surveys on topics that range from the basic principles of laser physics and laser dynamics, quantum optics, quantum aspects of the interaction of a few atoms and the electromagnetic field, and other fast growing areas of research. This book will be useful for graduate students and young researchers who wish to gain an introduction to the field of modern optics.