This book presents ideas about how mass movements work and the psychology of people that awaken/join mass movements. The author uses examples of movements of all types from the past, as well as movements that were current when the book was written; and discusses in great detail many techniques used to form and hold them together, the many motives that draw people to them, and the similarities between movements that appear on the surface to be completely different in nature (e.g., secular vs. religious, communist vs. fascist, radical vs. reactionary movements). The book is well referenced, and uses quotes from secular and religious writings (the Bible, too) associated with mass movements past and (the author's) present.

This book will be of great interest to anyone who is interested in: psychology, particularly of fundamentalism and blind faith, why some psychological conditions cause people to behave as they do, and the psychology of groups; the history of change through social upheaval and mass movements; how and why secular and religious extremist/fanatical groups come into being; and why there has been and continues to be so much injustice, violence and depravity on such large scales in "civilization".

The book does well at the author's stated intent to not judge the groups and personalities it discusses; however, it describes them so clearly that readers who are not good at honest introspection will probably recognize and judge themselves, and immediately feel an impulse to hate the author or declare him a blasphemer, and/or to ban the book (my local library thought it had the book, but when I wanted to borrow it they couldn't find it - I would not be surprised if a "true believer" started to read it and censored it from the library).