This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book provides present definitions but also traces how different dementia discourses have developed over time and across different cultures. It explains how other more humanising, person-centred and rights-based dementia discourses have taken hold in more recent years. The book then explains the different types of dementia that commonly affect people, outlines their main characteristics and the issues they create for people and discusses some of the risk factors associated with each type of dementia. It also sets out the demographic, social, financial, legislative and policy contexts in which social work practice with dementia takes place and explains how and why dementia has risen up the global public health agenda. The book focuses on the role that palliative care and advance care planning can play in improving the lives of people with dementia and their family carers.