Abstract
The article describes the history of attention-deficit/hyperactivity disorder (ADHD) from when it was described in characters in a children's book to the current definition and diagnostic criteria. Furthermore, it describes the history of therapeutic interventions including psychosocial interventions, medications and school interventions, and the evolution of thinking of the ADHD as a neurobiological condition. The information specific to children younger than 5 years, as well as the implications of the history of the condition on this age group, is discussed.