There's something to be said about a character's likability especially if the book's primary focus is "Is this guy gonna survive?!" If the reader doesn't like the guy then why continue reading? From the very start, it is easy to sympathize with Mark and to identify with him. His sense of humor is particularly enjoyable. A large chunk of the story is told through Mark's logs from Mars with intermittent jumps to NASA and his crew aboard their ship headed back to earth. There's a believability in all of the characters; even those only mentioned fleetingly. Despite being Andy Weir's first novel, his confidence in the logistics of space travel and attention to detail make this a very compelling read (science and math nerds will love it). Space travel has and will probably always hold a fascination for many readers of which I am undoubtedly one. I can't wait to see what Weir will come out with next! This is science fiction at its very best, ya'll.