I've enjoyed reading the work of Dr. Daniel Amen who has really been on what I consider to be the cutting edge of psychiatry. He has been using SPECT brain imaging to show how brains are functioning and the structurally visible representations of the disorders that have been previously diagnosed (as they have been for over a century) by rather subjective symptomology checklists. I find his work very impressive. One of his most popular books is Healing ADD: The Breakthrough Program that Allows you to See and Heal the 6 Types of ADD. His website is www.amenclinics.com. I find it fascinating to look at the functioning of the parts of the brain.