When Robert A. Heinlein completed his young adult novel Red Planet (1949), he felt he had enough unused background material for another book, which eventually became Stranger in a Strange Land. Heinlein’s Mars novels, like the works of Ray Bradbury and many other science-fiction writers, followed the speculations of astronomer Percival Lowell (1855-1916), who incorrectly postulated that Mars is or was populated by an intelligent species and that canals on the planet carry scarce water from the poles to the equatorial regions. Stranger in a Strange Land was one of the last major science-fiction stories published before the National Aeronautics and Space Administration launched exploratory probes that invalidated Lowell’s premises. Heinlein postulated Martians with mental powers so great that they previously destroyed a planet that formerly orbited the Sun between Mars and Jupiter.

In both of Heinlein’s Mars novels, the sharing of water is an important bonding ritual with deep emotional significance and meaning. In Red Planet, Heinlein describes an instance of the water-sharing ritual among native Martians. When Jill casually gives Mike a glass of water in Stranger in a Strange Land, they become “water brothers” and Mike trusts her absolutely although they have just met. Jubal Harshaw’s home has a swimming pool, which Mike considers the site of the ultimate religious experience. When Mike visits the Archangel Foster Tabernacle, he intentionally does not drink water.

Although Heinlein is usually associated with the political Right, he disapproved of religious fundamentalism and was deeply suspicious of organized religion in general. He was raised in Methodism, which at the time forbade playing cards, drinking alcoholic beverages, and dancing. He began to move away from this upbringing when he discovered the writings of Charles Darwin as a teenager.

The novel’s title is a biblical reference from the book of Exodus, chapter 2, verse 22. The title of the first section of the novel, “His Maculate Origin,” is a play on the doctrine of Immaculate Conception, which says that Mary, the mother of Jesus, was conceived without Original Sin so she could be a pure vessel for Jesus. Mike, by contrast, is conceived in an act of adultery. His name is derived from the Hebrew word Mikael, which means “one who is like God.”

In 1940, Heinlein wrote “If This Goes On—,” a cautionary tale about religious fundamentalism. His approach to criticizing religion in Stranger in a Strange Land and in his later book Job: A Comedy of Justice (1984) is satirical. This satirical element of the novel reaches its peak when Jubal, Gillian, and Mike visit the Archangel Foster Tabernacle. They enter through the Happiness Room, where they find slot machines and a bar. Then, they visit the Happy Thoughts medication chamber, where they see the preserved corpse of Foster, the religion’s founder. For the service itself, they sit in a luxury box, which has adjustable seats and a waiter to provide them with refreshments. Although it is hidden from view during the service, they are told there is a giant television screen that allows the church to function as a sports bar. The service itself includes a snake dance, a sermon, door prizes, commercials, and several hymns. Heinlein considered organized religion, regardless of its factual accuracy, to be a form of entertainment. He was also impressed by the success of L. Ron Hubbard, once a science-fiction writer and Heinlein’s contemporary, in founding the Church of Scientology and of Mary Baker Eddy, who founded the First Church of Christ, Scientist.

Heinlein uses place names to signify both water and Christianity. Bethesda Medical Center is a facility of the U.S. Navy, but in Heinlein’s future global society the United States no longer has armed forces. The name Bethesda comes from the Bible, in which it is a pool of water in Jerusalem believed to have healing powers. San Francisco and St. Petersburg are both located on peninsulas, and both are named for Christian saints.