The problem of the etiology of Alzheimer's disease has not been solved. But in the past several years there have been significant extensions of our knowledge of the disease and advances in determining the molecular changes underlying the disorder. There is now convincing evidence that the dementia per se is caused by loss of neurons and synapses, particularly in neocortex and hippocampus. The molecular aspects of amyloid and its precursor protein have been defined. The nature of intracellular changes leading to accumulation of the paired helical filament is beginning to be understood. For the first time, putative risk factors can be described in terms of pathogenetic mechanisms. Thus, it may become possible in the not‐too‐distant future to discover interventions that will slow the progress of this devastating disease.—Katzman, R.; Saitoh, T. Advances in Alzheimer's disease. FASEB J. 5: 278–286; 1991.