As Dr. Mercer posits, the fundamentalist is fundamentally driven by anxiety layered over a fragile sense of self-identity constructed upon a system of beliefs that is both logically inconsistent and highly suspect in light of modern science. As a result, the fundamentalist completely rejects modernity while battling mightily in the arena of national politics and culture to bring about a world that aligns more closely with the fundamentalist worldview.

Focusing on Christian fundamentalists, the author puts Christian fundamentalism in its historical and theological contexts. At the same time, Mercer calls upon cognitive theory to explain that the fundamentalist's life story is not particular to Christianity or any other religious belief system but that fundamentalist Catholics, Muslims, Jews, and those of all other faiths share a common psychological profile. Indeed, Mercer insists that if the Christian terminology were eliminated from contemporary fundamentalist Christian rhetoric, what would remain would be a framework that fundamentalists from other religions would find quite familiar and even comforting. In other words, the structure of the fundamentalist worldview, and the psychology beneath it, is pretty much the same across religions. It is a controversial thing to say about Christian fundamentalism, a thesis that has already proved contentious in the author's public appearances, and one that is sure to generate considerable attention and passionate debate as the U.S. populace continues to divide into opposing camps.