This book aims to identify and measure cognitive and social abilities in people with dementia and also in people with additional learning disabilities. Definitions of dementia are discussed in detail, outlining the neuropathology, neuropsychology and clinical signs of Alzheimer''s disease, and the neuropsychology of multi-infarct dementia. Discussion is made of the difficulties of a differential diagnosis and also the difficulties in assessing learning disability and dementia. A critique of instruments used in the clinical studies includes details of their reliability, validity, and standard error and norms of each tool. Empirical studies are presented together with the design and development of a neuropsychological test battery for the clinical assessment of people with dementia and learning disability. A link between cognitive performance and social abilities is presented for people with Down''s syndrome and dementia that highlights failure in the Central Executive System and Articulatory Loop System, important in normal memory. Emphasis is made on the need to improve and widen access in service provision for these valued people.