This book presents an interactional sociolinguistic approach to the progressive communicative breakdowns typical of Alzheimer"s disease. The language used in open-ended, naturally occurring conversations between the author and one elderly female Alzheimer"s patient over four-and-a-half years is investigated in an attempt to understand how the patient"s communicative abilities and disabilities are related, how they change, and how they are influenced by the behavior of the healthy interlocutor.