Profits of Religion by Upton Sinclair is a profound critique of religion, particularly as embodied by influential religious institutions. This lesser-known work from the author famous for The Jungle, delves into the intersection of power and ideology. Written at the outset of World War I, when international socialism was still seen as a feasible alternative to existing systems, Sinclair’s text is a testament to his unwavering commitment to social justice. His analysis is unflinching, exposing the hypocrisies within religious doctrines that perpetuate inequality and suffering among the marginalized. Sinclair argues that the collusion between religion and capitalist power structures hinders progress towards a more equitable society. He envisions a “new religion” grounded in human nature and scientific reasoning as the path to genuine societal transformation. This book provides an insightful look into early twentieth-century leftist thought, capturing the optimism and complexity of the era’s ideological debates.