Marc Lewis, a professor at Radboud University in Nijmegen, the Netherlands, is a cognitive neuroscientist known for his research on the development of emotions and personality in childhood and adolescence. His current work, based on an integrative review of the neuroscience of addiction, shows that addiction is not a pathological state but rather an unfortunate result of a brain doing what it's supposed to do -- in fact overdoing it: pursuing pleasure and avoiding risk. Accordingly, he argues that to understand addiction we need to stop thinking of it as a disease. Lewis's 2012 book, Memoirs of an Addicted Brain, is an account of his addiction to drugs as a young man, with accompanying explanations of the neurobiological processes underlying various drug experiences as well as the process of addiction itself. His new book is called The Biology of Desire: Why Addiction is Not a Disease.