Delirium, an acute disorder of attention and cognition, is a common and serious condition in elderly individuals, often leading to increased mortality and cognitive decline. Its diagnosis requires a formal cognitive assessment and a history of acute symptom onset. Multicomponent nonpharmacologic risk factor approaches are the most effective strategy for prevention, while pharmacologic prevention and treatment have shown limited effectiveness. Delirium may serve as a marker of brain vulnerability and a potential mechanism for permanent cognitive damage. Public health priorities include improving coding and reimbursement, research funding, and education for clinicians and the public about delirium. The article provides a comprehensive review of delirium, covering epidemiology, etiology, diagnosis, pathophysiology, evaluation, and management, with a focus on nonpharmacologic approaches. It also discusses current controversies and future research directions, emphasizing the need for more logical coding, public health initiatives, and improved clinical practices to address delirium.Delirium, an acute disorder of attention and cognition, is a common and serious condition in elderly individuals, often leading to increased mortality and cognitive decline. Its diagnosis requires a formal cognitive assessment and a history of acute symptom onset. Multicomponent nonpharmacologic risk factor approaches are the most effective strategy for prevention, while pharmacologic prevention and treatment have shown limited effectiveness. Delirium may serve as a marker of brain vulnerability and a potential mechanism for permanent cognitive damage. Public health priorities include improving coding and reimbursement, research funding, and education for clinicians and the public about delirium. The article provides a comprehensive review of delirium, covering epidemiology, etiology, diagnosis, pathophysiology, evaluation, and management, with a focus on nonpharmacologic approaches. It also discusses current controversies and future research directions, emphasizing the need for more logical coding, public health initiatives, and improved clinical practices to address delirium.