A Theory of Fun for Game Design, by Raph Koster

Rules of Play: Game Design Fundamentals, by Katie Salen, Eric

Game Design: A Brainstorming Toolbox, by David Perry and Rusel DeMaria

Game Design, by Bob Bates

Level Up! The Guide to Great Video Game Design, by Scott Rogers

Challenges for Game Designers, by Brenda Brathwaite and Ian Schreiber

Game Development Essentials: Game Interface Design, by Kevin Saunders and Jeannie Novak

The Complete Guide to Simulations & Serious Games, by Clark Aldrich