The trailblazing research on sleep mechanisms and petit mal epilepsy, conducted during the period from 1940 through 1970, illuminated the brain substrate for normal consciousness and attention, as well as their disorders. This research helped inform and structure our neuropsychologically based model of the "elements" of attention. The model has been used to assess attention in the research laboratory and clinic, and has led to a "nosology of disorders of attention," which is presented here in preliminary form. The nosology reviews the possible causes of the symptom(s) of impaired attention, as well as suggesting a blueprint for future research in this area.