Alzheimer's disease (AD) is a progressive and fatal neurodegenerative disorder manifested by cognitive and memory deterioration, progressive impairment of activities of daily living, and a variety of neuropsychiatric symptoms and behavioral disturbances. This article discusses worldwide prevalence patterns, history, and summarizes hypotheses about the causes of AD. Currently available diagnostic methods, their effectiveness of, and problems with, different methods and recent advances are thoroughly discussed. Finally, current treatment strategies are discussed in light of the benefits and drawbacks of different therapeutic approaches along with ongoing drugs under development.