This is the fourth book in the Neural Network series. It proposes an entirely new model for assessing and understanding how issues with attention are manifested. Currently, most individuals with deficit in attentional functioning are labeled with attention deficit hyperactivity disorder. This is because the current nosology is behaviorally driven and the target behavior for attention deficit hyperactivity disorder is the end stage global behavior, attention. The use of this nosology results in a large number of related but neuroanatomically different issues, from a neural network perspective, being lumped together. This results in a homogenous approach to the treatment of a heterogeneous cluster of problems and impedes research into the actual underlying network properties of specific forms of attentional problems. This book reviews and summarizes the current cognitive neuroscience regarding how attention is regulated in the human brain. It then details the various networks and processes that comprise attention and for each of these, details what could, and does, go wrong. This leads to a discussion of clinical assessment of these as yet unidentified "disorders" and recommendations for research and treatment. The book also has sections on the cognitive neuroscience of attention, models of attentional processing, a description of the neural networks involved in attention and a discussion of specific problems that arise when these network components fail to do their job correctly. The result of this work is a complete reformulation of the existing construct of attention deficit hyperactivity disorder which, in its current form, represents a plethora of disruptions of a multitude of attentional processes. The work challenges existing conceptual modeling and offers a new model for diagnosis and treatment, continuing to extend the authors' work in blending clinical neuroscience into the clinical practice of neuropsychology.