In June 2006, Morgan Kaufmann Publishers released Better Game Characters by Design: A Psychological Approach. The book is the culmination of Professor Isbister's 10 years of work in the interface agent and character design area.
Better Game Characters provides professional game developers and aspiring designers with a helpful and concise overview of concepts from psychology with direct relevance to game character design. Topics include facial expressions, body language, first impressions, social roles, and more. The book offers targeted design suggestions, mapped to the development process, and techniques for building character evaluation into the development cycle.
Better Game Characters includes interviews with industry experts on great character design, including Marc Laidlaw (of Half Life fame) and Tim Schafer. The book also includes interviews with researchers pushing the boundaries of social character design, and suggestions for incorporating their work into next-generation games.
You can order the book from Amazon by clicking this link.