Put your thinking cap on
When he wakes up at the beginning of the book the hero doesn't have a clue as to who he is or where he is. All he knows is that he's hooked up to a lot of tubes and a computer voice is asking him what 2 + 2 is. When he's finally able to answer that question, the computer allows him to progress in his recovery. As he gets stronger physically, he begins to have flashes of memories (including his name, Ryland Grace). Oh and he discovers there are two people long dead in the beds next to his and that he's in a ship in space. Ryland is all alone and millions of miles away from home.