Generally considered a social and/or recreational activity, in some cases gambling can become an addictive behavior. Pathological gambling is classified by the Diagnostic and Statistical Manual of Mental Disorders (DSM) as an impulse control disorder, characterized by failure to resist the impulse to gamble despite severe and devastating personal, family, or vocational consequences. The lifetime prevalence of pathological gambling in the adult population of North America has been estimated to be over 1%. Pathological gambling can also be associated with significantly specific behavioral problems and neuropsychiatric conditions, mainly affecting dopaminergic reward pathways. This book provides a 360-degree overview on the current psychological models for gambling behaviors, informed by both neurobiological and clinical observations.