of the person. As such, it is arguably the broadest, most "philosophical", branch of psychology. It involves an examination of the effects of genetics, the physical environment, culture, upbringing, trauma, pathology and more. In as much as this is clearly a huge undertaking, it is as much a matter of competing theories as it is of empirical research. For this reason, it remains a tradition in the field to look at various attempts over the last 100-plus years to tackle the issue: "What is it to be a person?" This book attempts to provide an open-minded review of the most important of these theories.