In the 1970s, Troup’s father was one of millions who purchased a book called The Late Great Planet Earth, which interpreted events in Israel as evidence that the great war of Armageddon would happen by the late 1980s. The non-fiction bestseller of the decade, it was followed by the wildly popular end times conspiracy tome The New World Order, by the televangelist Pat Robertson, and then the Left Behind novels and films, which concerned violent clashes in Israel that would bring about biblical prophecy.

To outsiders, these pieces of doomsday pop culture seem like far-fetched lunacy. For millions of ...