Level Up! The Guide to Great Video Game Design by Scott Rogers is a classic of video game design. This book contains a huge amount of great information along with very useful appendices containing sample design documents, lists of story themes and environments, and templates for designing enemies and bosses.
If you are designing video games and apps, this book is a must read if only to provide you the necessary background and history of the field. Don't reinvent the wheel -- you need to know this information to know what other games have done and how they did it. Get this book. Read it. And then design your next game!