The demographics of ageing suggest a great need for an early diagnosis of dementia and for the development of preventive strategies. Neurodegeneration in Alzheimer's disease is estimated to start 20-30 years before clinical onset, and the identification of biological markers for pre-clinical and early diagnosis is the principal aim of research studies in the field. In this book, the authors present topical research on Alzheimer's diagnosis including cerebrospinal fluid biomarker Amyloid-B 1-42 identification; visual impairment in Alzheimer's disease; cerebral glucose metabolism through F-fluoro-deoxy-glucose positron emission tomography and neuroimaging.