Gustave Le Bon

Gustave Le Bon (7 May 1841 – 13 December 1931) was a French social psychologist, sociologist, and amateur physicist. He was the author of several works in which he expounded theories of national traits, racial superiority, herd behavior and crowd psychology.

His work on crowd psychology became important during the first half of the twentieth century when it was used by media researchers such as Hadley Cantril and Herbert Blumer to describe the reactions of subordinate groups to media.

He also contributed to controversy about the nature of matter and energy. His book The Evolution of Matter was very popular in France (having twelve editions), and though some of its ideas—notably that all matter was inherently unstable and was constantly and slowly transforming into luminiferous ether—were used by some physicists of the time (including Henri Poincaré), his specific formulations were not given much consideration. In 1896 he reported observing a new kind of radiation, which he termed "black light" (not the same as what modern people call black light today), though it was later discovered not to exist.