This book is a true classic on Linux game programming. It is written by the creators of SDL and founders of Loki Software, and covers lots of things a game programmer should care about when using Linux & SDL.
Of course you can buy a printed copy of this book, but for all those poor guys there are legel(?) PDF versions of this book available. I found a free e-book copy here, but this can be off another day. Better search on your own.