Tim LaHaye died last week. He was 90. He was best known for co-writing the “Left Behind” series of novels about the battle of Armageddon, which fundamentalists believe will follow the Rapture of Christian believers from earth. The books have sold over 63 million copies—the version of the series for kids has sold 11 million copies alone—and the obituaries led with that. He helped found the Moral Majority with Jerry Falwell and sat on its board, and in 1981 began the Council for National Policy, a secretive directorate for religious-right organizations that has been called “the most powerful conservative organization in America you’ve never heard of.” He was so fanatically devoted to what Christians call “the Great Commission”—Matthew 28:19–20: “Go therefore and make disciples of all the nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all things that I have commanded you”—that when he once ran into the Dalai Lama in Israel he shook hands with him and asked, “Sir, has anyone ever explained to you who Jesus Christ really is?”

An aide to the incarnation of the Bodhisattva rebuffed LaHaye, leaving His Holiness the Dalai Lama walking the long path to the unbelievers’ Lake of Fire.

But LaHaye’s greatest contribution to the power of fundamentalist Christianity in America was more subtle, and, on the surface, sounds like a hilarious joke.

At the time ministers like LaHaye began politicizing en masse against the fruits of the moral lassitude of the 1960s—gay rights, abortion, secular humanism in education, feminism, and all the rest—Protestant fundamentalism was suffering from a gaping deficiency as a social movement, betokening its parochial roots: its insularity, its joylessness, and a befuddled inability to compete with the blandishments of liberal, modern therapeutic culture.

Their flocks looked longingly upon the worldliness forbidden them. Earlier generations of preachers would have simply forbade with greater intensity. Figures like the LaHayes (husband and wife), James Dobson, and Pat Robertson created a Christianity that would embrace what the modern world offered, up to a point. They were so successful that by the time of Ronald Reagan’s second successful presidential run, fundamentalist Christianity comprised an entire parallel universe within which one could live fully, eschewing the outside world as utterly wicked even as the Christian world came more and more to resemble it.

Depressed? Anxious? Bored? Bible reading not cutting through the fog? Turn to Dr. James Dobson, a psychotherapist with impeccable secular credentials whose Christian-inflected self-help books like Dare to Discipline (1970) and What Wives Wish Their Husbands Knew About Women (1972), and “Focus on the Family” seminars and videos had become so popular by 1977 that he quit his therapy practice and incorporated a nonprofit organization that produced a weekly 30-minute radio phone-in show. Or if Dobson doesn’t do the trick, call in to the Christian Broadcasting Network’s crisis counseling service, with a staff of 6,000 friendly ears, fielding 1.25 million calls in the first half of 1976 alone. (“Most calls concern potential suicides, alcoholics, unwed mothers, drug abuses, and marital problems,” the Los Angeles Times explained. “Literature is sent to callers and complex cases are offered professional help.”)

Looking for worldly purpose? Try politics. Need a night out? There were “Christian” movies, like Russell Doughten’s four-part A Thief in the Night series.

Or, why not stay in and have some fun?

In 1976, LaHaye and his wife Beverly, who as the founder of Concerned Women of America nearly equaled her husband in influence, published a book called The Act of Marriage: The Beauty of Sexual Love. It was, yes, a Christian sex manual, one which indubitably added to the sum total of joy in the world because it insisted that erotic ecstasy was not something forbidden for Christian couples but required of them. “Modern research has made it abundantly clear that all married women are capable of orgasmic ecstasy. No Christian woman should settle for less.” “Sexually illiterate” men, and “selfish lovers” were excoriated.

With Masters and Johnson, the LaHayes agreed that the vaginal orgasm was a myth, which meant careful study of clitoral response was a must for Christian sexual literacy. And it was in the Bible—where, in the most curious exegesis in the history of Christendom, the LaHayes discovered the proper Scriptural method for manual-vaginal stimulation: “The wife lying on her back with her knees bent and feet pulled up to her hips and her husband lying on her right side.” Just like the Song of Solomon advised, Chapter 2, Verse 6: “Let his left hand be under my head and his right hand embrace me.”

Nor was the hubby’s stimulation neglected: the book included a chart where women could record daily progress on their Kegel exercises.

Funny, yes. Serious, too. Books like The Act of Marriage—and Tim’s earlier, tamer, 1968 publication, How to Be Happy Though Married—were part of a movement without which the darkness the Christian right has visited on our land would not have been possible. They helped make of fundamentalism an entire, enveloping world. All the better for them to get to work enveloping our world, too.