The Art of Game Design
Games are an extreme case of interaction design, making this book a complete introduction to IXD and UX.
Schell structures his book around thinking "lenses" — multiple perspectives you can try on when evaluating a design. Each lens comes with an introduction and questions that can be used as design prompts.
Along the way, the book also covers the basics of agile development, project management, team structure, creative brainstorming, how to get past creative block... it's quite a tour.