Presented in an interesting, historical and philosophical way, this book describes the current state of play in brain imaging, showing the differences among the different imaging modalities, and reviewing the knowledge about the chemical reactions in the brain, and their relationship to thinking, feeling and acting. The book reviews all the results of PET and PET/CT imaging of the brain with all radiopharmaceuticals that bind to receptors in all recognized and classified mental diseases, as well as the studies on the localization of those sites that are activated by sensory or motor activity. The book illustrates the parts of the brain activated and deactivated during sensory perception, motion and other mental functions and explains how the process of neurotransmission takes place in chemical terms.