"No and Yes," like preceding work of Dr. René A. Spitz, is a study of the psychological development of infants. In this work Dr. Spitz focuses upon the beginnings of verbal and somatic communication, and his purpose is to apply the psychoanalytical theory of Freud to this problem. It is Dr. Spitz's proposition that negation, as well as affirmation, arises out of inherited motor-behavior patterns which are used in the earliest nursing situation. Thus, negation, or no, arises from cephalogyric movements involved in breast-feeding. References are made to recent investigations of animal ethology, physiology, embryology, and experimental psychology in a most stimulating manner. However, in elaborating his own thesis there is a paucity of original observation. Major emphasis is placed upon the case of Monica, a girl with esophageal atresia who was fed through a gastric fistula until she was twenty-two months old, described by Engel, Reichsman, and Segal (Psychosom.