My favorite "nonfiction" book is BORN ON A ROTTEN DAY, by Hazel Dixon-Cooper. Inside, you'll find all the info you'll need when wondering why your family members, co-workers, friends, spouse(s), kids, and YOU are crazy. It's very helpful when character building in fiction writing. Creating new characters is a complete joy when you can assign them a birthday then go read about that sun sign. Characters practically create themselves.