The Martian is a science fiction novel written by Andy Weir. It tells the story of Mark Watney, an astronaut who is left stranded on Mars after his crew mistakenly believes he is dead. With limited supplies and no way to communicate with Earth, Watney must use his ingenuity and scientific knowledge to survive on the hostile planet. The book combines elements of survival, science, and humor to create a gripping and realistic portrayal of life on Mars.