Dementia is amongst the greatest challenges facing the medical profession as the population ages. Accurate diagnosis is essential as many rarer forms of the disease are treatable if recognized early. This collection of case studies from around the world illustrates both common and unusual causes of dementia, emphasizing clinical reasoning, integrative thinking and problem-solving skills. Each case consists of a clinical history, examination findings and special investigations, followed by diagnosis and discussion. The aim is to reinforce diagnostic skills through careful analysis of individual presenting patterns, and to guide treatment decisions, using state-of-the-art diagnostic classification and tools. The reader will be able to distinguish patients who need reassurance, closer follow-up or immediate referral to specialized services. Written and edited by internationally recognized experts in dementia, these case studies will inform and challenge clinicians at all stages of their careers.