The chief founder of social psychology was Gabriel Tarde (1843–1904). He wrote the first important treatise in the field of the psychology of society. The _Lois de l’imitation_ established Tarde’s reputation as a social psychologist, and at the same time aroused the world of thought to the existence of a new phase of social science. Tarde was a jurist who inquired into the causes of anti-social conduct. He was greatly impressed by the observation that criminal acts are committed in waves. Upon examination of this fact he found imitation to be a potent factor, and began to analyze the laws of imitation. This study soon showed that not all is imitation but that much human conduct arises out of opposition. His analysis of the laws of opposition led him to the conclusion that imitation and opposition are the bases of a third social factor, invention. The social process, as he observed it, is characterized (1) by an ever-widening imitation of inventions, (2) by the opposition of conflicting circles of imitation, and (3) by the rise of new inventions (out of these oppositions), which in turn become the centers of new imitations. Thus, the social process goes on, endlessly and unconsciously or consciously. To understand society, Tarde believed that one must understand how minds act and interact. Tarde’s work, first presented is _Les Lois de l’imitation_, was formally developed in his _Logique sociale_, and summarized in his _Lois sociale_ (English translation, _Social Laws_). Together, these books constitute a unique social theory. Although Tarde’s approach to the psychology of society was objective and sociological, and although he did not give serious attention to the purely psychological nature of the mind nor to the instinctive bases of conduct, he nevertheless made a contribution to social thought which is valid and enlightening. Society, according to Tarde, is a group of people “who display many resemblances, produced either by imitation or by counter-imitation.”[XXII-7] Again, he says that society is “a group of distinct individuals who render one another mutual services.”[XXII-8] Societies are groups of people who are organized because of agreement or disagreement of beliefs.[XXII-9] “Society is imitation.”[XXII-10] The outstanding element in social life is a psychological process in which inventions are followed by imitations, which when coming into inevitable oppositions produce new inventions.