The scientific literature has expanded dramatically in recent years, making entry into the structure of any given area extremely difficult; concurrent with this explosion more people are required to become acquainted with information outside their main line of expertise. For this reason there is a need for review articles which give an overall review of circumscribed areas. This volume reviews the subject of respiratory control mechanisms; the authors of each chapter are active research workers engaged in the area covered by their chapter. The first four chapters are concerned with the basic physiological mechanisms which sense changes in the respiratory system, in the standard physiology textbook parlance chemical and neural sensory receptors. The peripheral arterial chemoreceptors sense changes in arterial oxygen tension, carbon dioxide and pH. The first chapter describes the basic responses in the organ produced by changes in blood chemistry. Later chapters discuss changes in activity produced by exercise, chronic hypoxia and the possible role of the chemoreceptors in initiation of respiration in the new-born. In Chapter 1, a section considers the action of drugs on the peripheral chemoreceptors, and finally there is a discussion of the possible mechanisms whereby the organs sense changes in blood chemistry. This pattern is followed in subsequent chapters wherever possible; first a discussion of the basic physiological properties, followed by any clinical application and dis­ cussion of the mechanism whereby the receptor might operate. The remaining chapters are of a more applied nature.