The Ten Faces of Innovation: IDEO's Strategies for Defeating the Devil's Advocate and Driving Creativity Throughout Your Organization. Tom Kelley. Currency Books, 2005. 

Kelley is one of the founders of IDEO. Over time, the people at IDEO have observed ten people-centric roles that they use to encourage different innovative points of view. There is a discussion, along with real examples, about each role and how to develop one’s talents to adopt that point of view. The book has a website.