The last two decades have seen psychogeriatrics transforming into a fast-moving, science-led specialty. This is particularly so in the field of dementia, spurred on as it so often is, by the findings of high-tech neuroimaging and molecular pathology. Clinicians are required in their daily practice not just to make the traditional diagnostic distinctions between dementia, delirium, pseudodementia and “normal aging,” but are expected in this new world also to recognize a series of different dementia subtypes, including Alzheimer's disease (AD), cognitive vascular impairment (CVI), dementia with Lewy bodies (DLB), fronto-temporal dementia (FTD) and prion disease. The list could go on and on (and sometimes does). We also know from autopsy studies that mixed pathology dementia cases are common and that our clinical diagnoses should take this into account.