Red Dwarf by Grant Naylor (1996, Paperback, Reissue)

Classic fish out of water story about a man named Lister, who joins the Space Corps to get back to earth, then through a series of follies ends up 3 Million years in the future, the sole survivor of the human race, who along with a creature who descended from cats and a holographic copy of his dead bunkmate, find themselves in the adventure of a lifetime trying to turn the ship around and get back to Earth. Not just a great story, hilarious to boot.