In recognition of the fact that attention deficit hyperactivity disorder (ADHD) is a complex disorder, with the co-occurrence of other psychiatric disorders being among the most challenging complications, this textbook provides a comprehensive review of how ADHD relates to other disorders and how this interaction can be effectively recognized and treated. In addition, the book provides updated information about developmental aspects of ADHD not current in its preceding volume (Attention-Deficit Disorders and Comorbidities in Children, Adolescents, and Adults, published in 2000). To my knowledge, there are few definitive textbooks that cover this clinical disorder over the life span and provide a developmental context for its various presentations over time. Moreover, phenomenological descriptions are not limited to DSM criteria but rather integrated with the rich knowledge gained about this disorder from the field of neuroscience. After establishing the developmental complexities, genetics, and common presentations of ADHD from preschool to adulthood, the body of the book focuses on the co-occurrence of the disorder with a variety of psychiatric syndromes, including mood and anxiety disorders, oppositionality and aggression, obsessive-compulsive disorders, language and learning disorders, substance use disorders, autism spectrum disorders, developmental coordination disorder, sleep disturbances, and Tourette's syndrome. This thematic organization is helpful not only to a clinician but also to educators and laypersons, who might observe attentional problems manifested in a variety of different contexts outside of a clinical setting.