First published, Enthusiasm is the product of thirty years of research and inspiration. In his perceptive and learned study Knox presents the personalities and religious philosophies of the various types of enthusiasts of the seventeenth and eighteenth centuries.

Enthusiasm, first published in 1950 by Ronald A. Knox, is the end product of thirty years of research and inspiration. In his perceptive and learned study Knox presents the personalities and religious philosophies of the various types of enthusiasts of the seventeenth and eighteenth centuries: the monatists; donatists; anabaptists; Quakers; Jansenism; quietism; methodism; and other movements.