The French philosopher and sociologist Jean Gabriel Tarde (1843-1904) made important contributions to general social theory and to the study of collective behavior, public opinion, and personal influence.

Jean Gabriel Tarde was born in Sarlat, the son of a military officer and judge. His father died when he was 7, and Jean Gabriel was raised by his mother. He attended a Jesuit school in Sarlat, obtaining a classical training, and read law in Toulouse and then Paris. From 1869 to 1894 he held several legal posts near Sarlat. Only after Tarde's mother died did he agree to leave Sarlat, and he accepted a position as director of criminal statistics at the Ministry of Justice in Paris. After 1894 he lectured in numerous peripheral institutions outside the university, and from 1900 until his death he held the chair of modern philosophy at the Collège de France.

In the last 2 years of his...