Earthling Marvin Flynn has done some traveling, if you can call it that. He’s gone scuba diving down to the sunken city of Miami. He’s seen the Hanging Gardens of London. He’s crossed Sinkiang by camel. But he’s never been anywhere truly exotic, not even the moon. Real travel costs real money. And he hasn’t got it.

Which makes the classified ad he comes across all the more tempting. It offers the opportunity to swap minds with a self-described “Gentleman of Mars.” See Mars through Martian eyes, all while avoiding the expense of a trip across the solar system? Who could say no? Brushing off a friend’s warning—think of what he could do with your body! —Flynn accepts. He soon finds himself in the body of a Martian, which might be all right if it weren’t for the lisp—and if it weren’t for the fact that another would-be tenant wants to claim the body himself.

To clear up the question of who has rights to live in the Martian’s body, the hero and the accuser head to the police station. “It is a truism throughout the civilized galaxy that when you go to the police, your troubles really begin,” Sheckley writes, and then he demonstrates why it’s a truism.

The hero quickly discovers that the “Gentleman of Mars” who swapped minds with him is a criminal. Flynn finds himself tossed on the proverbial sidewalk, barely escaping death by swapping into another body, that of an egg catcher. And these are Martian eggs: the kind that talk. And the beings who lay these eggs? They’re big, and deadly, and they don’t like egg catchers. No problem: he can Mindswap again. But who will he be next?

His adventures will take him into the disorienting worlds of wealth and love; to the Old West (well, sort of); and into contact with people (or “people”) who speak with Shakespearean brio or Lewis Carroll-style illogic. He’ll learn to wield a sword, like someone out of The Three Musketeers. He’ll face off with the scofflaw who made off with his face (and his body), and he’ll learn just how much home can change when you’ve been away. In short, he’ll have quite the vacation.