Attention deficit hyperactivity disorder (ADHD) is one of the most prevalent childhood psychiatric disorders of our time. The condition is defined by levels of inattention, hyperactivity and impulsivity that are in impairing and developmentally inappropriate. Increasingly, there is a growing appreciation that for many individuals the disorder may persist into adulthood and be associated with significant social and economic burden. Conditions, such as ADHD, that are manifestly heterogeneous in terms of their clinical presentation, underlying neurobiology and treatment response, must be tackled on multiple fronts. This Handbook of Attention Deficit Hyperactivity Disorder provides a state of the art position on each of these fronts from leading clinicians and researchers from around the world. Broad in its scope and comprehensive in its detail, this book should be as useful to the student as it is to the experienced clinician or researcher.