Total Recall — Philip K. Dick

Philip K. Dick's classic short story tells the story of Douglas Quail, an unfulfilled bureaucrat who dreams of visiting Mars, but can't afford the trip. Luckily, there is Rekal Incorporated, a company that lets everyday stiffs believe they've been on incredible adventures. The only problem is that when technicians attempt a memory implant of a spy mission to Mars, they find that real memories of just such a trip are already in Quail's brain. Suddenly, Quail is running for his life from government agents, but his memories might make him more of a liability than he is worth.