The appeal of united action and self-sacrifice is the book’s major theme. It is also the subject of Part 3, by far the lengthiest of the book’s four parts. The true believer’s desire for united action and self-sacrifice defines a mass movement and serves as its main draw for adherents.

Eric Hoffer establishes this major theme from the beginning. In the book’s second paragraph, he explains that “[a]ll mass movements generate in their adherents a readiness to die and a proclivity for united action” (xi, emphasis added). The important point is that those who become true believers already want these things. They find their individual lives unbearable. They “crave to be rid of an unwanted self” and thus feel an intense “passion for self-renunciation” (12). In fact, united action and self-sacrifice are so central to a mass movement that the moment it starts to appeal to career-minded people is the moment it ceases to be an active movement.

For the true believer, joining a mass movement conjures powerful emotions, some of which can be akin to a religious experience. The relinquishing of one’s self often constitutes “an act of atonement,” which requires “a poignant sense of sin” (54).