Dr. Barkley has developed one of the leading theories of executive functioning (EF) and its role in the the nature of ADHD. This theory is based on understanding the nature of the executive neuropsychological functions as a multi-level meta-construct and its contribution to self-regulation across time to support the individual\\\'s long-term goals and general welfare. In Part I of this course, he discusses the nature of EF and some of the problems that exist with its definitions in the clinical and research literature. He then shows how the executive functions can be understood as actions that are being self-directed in order to engage in self-regulation across time toward one\\\'s goals. Each EF is a type of action-to-the-self and Dr. Barkley describes the nature of each of these self-directed actions and the specific mental abilities they provide for self-regulation. He concludes with a discussion of the implications of this theory of EF for understanding the nature of ADHD as a disorder.