ABSTRACTAlzheimer's disease is one of the most devastating brain disorders of elderly humans. It is a decade has witnessed a steadily increasing effort directed at discovering the etiology of the disease and developing pharmacological treatment. Recent developments include improved clinical diagnostic guidelines and improved treatment of both cognitive disturbance and behavioral problems. Symptomatic treatment mainly focusing on cholinergic therapy has been clinically evaluated by randomized, double-blind, placebo-controlled, parallel-group studies measuring performance-based tests of cognitive function, activities of daily living, and behavior. The role of estrogen replacement, anti-inflammatory agents, and antioxidants is controversial and needs further study. Antidepressants, antipsychotics, mood stabilizers, anxiolytics, and hypnotics are used for the treatment of behavioral disturbance. Future directions in the research and treatment of patients with Alzheimer's disease include: applying functional brain imaging techniques in early diagnosis and evaluation of treatment efficacy; development of new classes of medications working on different neurotransmitter systems (cholinergic, glutamatergic, etc.) Keywords: Dementia, Symptoms and Stages of disease, Etiology, Pathology, Neurophysiology, Risk factors, Causes, Diagnosis, Treatment, Prevalence,