The Profits of Religion

The Profits of Religion: An Essay in Economic Interpretation is a nonfiction book, first published in 1917, by the American novelist and muck-raking journalist Upton Sinclair. It is a snapshot of the religious movements in the U.S. before its entry into World War I.
The book is the first of the "Dead Hand" series: six books Sinclair wrote on American institutions. The series also includes The Brass Check (journalism), The Goose-step (higher education), The Goslings (elementary and high school education), Mammonart (art) and Money Writes! (literature). The term "Dead Hand" ironically refers to Adam Smith's concept that allowing an "invisible hand" of individual self-interest to shape economic relations provides the best result for society as a whole.
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."