This chapter discusses the relationship between the clinically observed “plaques and tangles” of Alzheimer’s disease (AD) and the observed behavioral course of AD. In the United States, AD is the sixth leading cause of death for all age groups, after heart disease, cancer, respiratory diseases, accidents, and stroke. Studies have indicated that a large majority of the approximately 1.4 million residents in nursing homes in the United States manifest a dementia syndrome generally associated with AD. The clinically observable symptomatology of AD dramatically changes in form from the earliest manifest deficits to the most severe stage; therefore, recognition and differentiation of the stages of this illness are imperative for proper diagnosis, prognosis, management, and treatment. Anger and other more overt behavioral symptoms of AD, such as anxieties, paranoia, and sleep disturbances, are frequently evident.