One of the oddities of the exploding field of brain science is that very few researchers are exploring the one area that arguably makes us most human -- our creativity. Part of the reason is that it's devlishly difficult to measure and to assess.
Nancy Andreasen, a University of Iowa professor and a pioneer of brain research, is one of the small group that continues to explore the creative urge.
This book is a good overview of what she knows about creativity both from self-reports by highly creative people and from the studies she has done, largely using authors who paticipate in the renowed Iowa Writers Workshop.
Andreasen also is one of the few to rigorously explore the connection between high levels of creativity and mental illness, and she has found that highly creative people, and many of their relatives, do have a greater propensity to suffer from mood disorders, particularly mania and depression. On the other hand, she notes that almost all the authors and others she has interviewed note that they are at their least creative when they are sick, and so she doesn't make the mistake of lauding insanity as a sort of template for achieving great work.
The book also contains good primers on brain organization and function, and in the end, some practical suggestions for how we can all promote more creative thinking in ourselves and our children (among the ideas: spend a half hour a day deeply exploring a new subject you know nothng about; or spend an equal amount of time letting your mind "wander" without outside distraction). Ideas like these are based on the finding that our brains remain plastic and capable of rewiring throughout our lives, and on evidence that creative people have their strongest activity in the "associative" areas of the brain that link different functional sectors together. "The key thing," she writes, "is to let your mind wander freely and to go to 'that place' where ideas and images rise to the surface from unconscious or preconscious sources, form or float or fly, ultimately colliding and connecting to create novel associations that cannot occur easily through consciously willed 'brute force' cogitation."