Alzheimer's disease (AD) remains the leading cause of dementia worldwide and an escalating global health crisis. The hallmark amyloid plaques and neurofibrillary tangles (NFT) are now known to be accompanied by a complex array of pathologies that culminate in neurodegeneration and cognitive decline. New disease-modifying therapies for AD can now slow cognitive decline through the removal of amyloid plaques from the brain, but treatments to stop or prevent cognitive impairment remain elusive. In this review, we summarize the most recent updates in AD research on pathologic disease mechanisms and therapeutic strategies, highlighting advancements in apolipoprotein E (APOE) biology, neuroimmunology, biomarker discovery, and initial experience with new disease-modifying therapies. These important discoveries are revolutionizing AD diagnosis and treatment and provide hope for a future where AD is not only treatable but also preventable.