As population aging spreads to more parts of the world, dementia is fast becoming one of the most common and feared conditions of our time. Diagnosis has been identified as a key point of intervention for both biomedical and policy agendas. Drawing on ethnographic research spanning more than a decade, this book reflects on observations and recordings of UK memory clinic consultations, interview accounts with clinical staff involved in assessment and diagnosis, internationally recognised dementia researchers, and people living with dementia and their families both at the point of diagnosis and as their condition progresses. In dialogue with accounts and observations from the field, this book makes the case for the development of a sociology of dementia diagnosis. In doing so, the book progresses a dialectic approach to the study of dementia construction and experience and contextualises dementia diagnosis within wider networks of meaning and systems of value related to aging, health, and personhood.