Crying is a typical human expression of emotion. Surprisingly, until now little scientific attention has been devoted to this phenomenon. Many textbooks on emotion fail to pay attention to it, and in scientific journals there are hardly any contributions focusing on this behavior. In contrast, there is much interest from the lay public, allowing pseudo-scientists to formulate theories that have little or no scientific basis. Is there any evidence in support of statements that crying is healthy or that not crying may result in toxification? How do people react to the crying of others? Is crying important for the diagnosis of depression, and if so, how? This book aims to fill this gap in scientific literature. Crying is discussed from several perspectives and specific attention is given to methodological issues and assessment. Each chapter provides a review and a summary of the relevant scientific literature.