Dr. Comings tells the story of his 18 years of involvement with Tourette syndrome, from both the level of treating thousands of patients with this common and complex disorder, to his clinical, genetic and molecular genetic research. He quickly realized this was more than just a tic disorder. His patients and their relatives had problems with a wide range of behaviors including attention deficit hyperactivity disorder (ADHD), obsessive-compulsive behaviors, conduct and oppositional defiant disorder, rages, mania, depression, anxiety, panic attacks, phobias, sexual, sleep, and other disorders. Because Tourette syndrome is genetic, this involvement with a spectrum of disorders had broad implications about the causes of behaviors that most mental health workers attributed to psychological problems, poor parenting, or learned behaviors. His genetic studies led him to eventually conclude that Tourette syndrome was a polygenic disorder caused by the coming together from both parents of a number of genes affecting dopamine, serotonin and other brain chemicals. Dr. Comings relates how the concept that many human behavioral disorders were genetically interrelated was initially ridiculed. These attitudes began to change as other reported similar findings and as his concept gained support from molecular genetic studies of specific genes.