The Profits of Religion: An Essay in Economic Interpretation is a non-fiction book by the American novelist and muckraking journalist Upton Sinclair, first published in 1917. It is a snapshot of the religious movements in the U.S. before its entry into World War I. In this book, Sinclair attacks institutionalized religion as a "source of income to parasites, and the natural ally of every form of oppression and exploitation."