Alzheimer disease (AD) is one of several types of chronic and very common dementing disorders, affecting individuals aged 65 years or older. During the last five years, an enormous growth in the field has enriched our understanding of this complex condition. Molecular genetic studies have identified at least three genes that, when mutated. cause the autosomal dominant, early-onset familial form of the disease. The late-onset. most common forms of the disease are likely to be associated with various genetic susceptibility factors. The application of cell biological techniques has given insight into basic aspects of the functions of important proteins involved in disease progression. and transgenic animal studies have further enriched our knowledge of the pathophysiological aspects of the disease. More efficient therapeutic drugs to retard its progression have been developed, as well as techniques to identify the preclinical phase of the disorder. Although we are st ill lacking the molecular basis and order of events involved in the disease process, the future for AD research, as well as for AD patients, is more promising than ever before.