Last weekend, Elon Musk announced that his artificial-intelligence startup, xAI, was launching a chatbot with “a bit of wit” and “a rebellious streak,” known as Grok. As Musk explained, Grok is modeled on the Hitchhiker’s Guide to the Galaxy, a snarky manual for interstellar travelers that the humorist Douglas Adams concocted for his classic 1979 novel of the same name.

The origins of the chatbot’s name, however, lie in an entirely different work of science fiction. “Grok,” a verb meaning “to understand deeply or intuitively,” was coined by Robert Heinlein for his 1961 novel “Stranger in a Strange Land.” In Heinlein’s tale, a human born and raised on Mars is brought to Earth as an adult and displays psychic powers.