1 Book to read for 2 months

[bogey]

So I am going on a 2 month trip and want to bring along a book or maybe 2 to read on it. I don't want to carry more than that though, so I need the book to have a lot of depth to it. I would appreciate any suggestions.

Right now I think I am probably going to bring Godel, Escher, Bach and possibly Mathematics of Poker.

I want books that will really challenge me and am leaning away from fiction (so not really interested in Ulysses or something like that). Bonus points for teaching me something that could have a direct effect on making me money, so I would be interested in maybe some investing type books.

Thanks for any suggestions