The French sociologist and economist Pierre Guillaume Frédéric Le Play (1806-1882) had widespread influence through having been one of the first to develop and use the social-survey method of investigation.

On April 11, 1806, P. G. F. Le Play, was born at La Rivière, Saint-Sauveur (Calvados). He was graduated with honors from the École des Mines in 1840, subsequently was appointed to a professorship in metallurgy there, and served as coeditor of the Annales des mines. He was invited to visit various nations to study conditions and reorganize their mining industries. During the course of these extensive travels he kept careful notes on the conditions of workers and their family life. In 1848 he resigned his professorship to devote full time to social science studies and the development, refining, and publicizing of his theory of social reform.

Le Play's first important work, European Workers (6 vols...