Set in the taverns of Paris, this is perhaps the first classical tragedy of working-class people living in the slums of a city. The Drinking Den (1877) is part of the Rougon-Macquart series, a naturalistic history of two branches of a family traced through several generations. Zola's work was influenced by contemporary theories of heredity and experimental science, and the behaviour of the two families is shown to be conditioned by environment and inherited characteristics, chiefly drunkenness and mental instability.