A lawyer interested in criminological ideas, his first works were critical of the environmental focus of the Italian criminologists such as Lombroso. He became Director of Criminal Statistics in the French Ministry of Justice. Tarde adopted a psychologistic approach and in the 1880s began to write more generally about processes of ‘imitation’. He saw societies comprising a small minority of creators and innovators and a mass of followers who simply imitate the actions of those they see around them. Imitation, then, is a basic means of cultural transmission (The Laws of Imitation, 1890). He saw innovations spreading through societies along chains of imitation, radiating out in networks of diffusion, and his work has been influential among those studying the diffusion of innovations. Following his appointment as a professor in the Collège de France, he wrote on opinion and crowd behaviour. His individualism brought him into conflict with Durkheim. One of his least known works is a science fiction novel on the consequences of global climate change (Underground Man, 1896).