Sternberg's Handbook has an almost mythical reputation amongst the Creative Studies Students at Buffalo State College. While there are shortcomings to the Handbook, areas where key authors or subjects are missing (it is written from the behavioral scientist point of view, and there are other, equally valid viewpoints in creative studies), each chapter will have plenty of food for thought.
And, guaranteed, you will have the time to digest this food for thought, as each and every chapter requires slow and careful reading. If the writing were to be any denser, it would tear free from the pages and sink to the very center of the Earth! Yet, there is so much information that, in the end, the knowledge derived is more than worth the work needed to get at it.
One last note: This is a handbook for those interested in the deep research on creativity. It is NOT suitable a "first book" for anyone starting out to learn about creativity!