The document provides revised guidelines for the neuropathologic assessment of Alzheimer's disease (AD). Key changes from the 1997 criteria include: 1) separating the clinical diagnosis of AD from the neuropathological assessment of AD changes, 2) emphasizing the assessment of co-existing brain pathologies that may contribute to cognitive impairment, and 3) providing updated guidance on the neuropathological changes of AD and other common diseases seen in aging and dementia.