Trust is an important cornerstone of every human relationship. A loss of trust leads to significant stress, uncertainty, and life crises. Regaining trust in a relationship is one of the most complex social processes in psychology. The book explores the question of what concepts of trust psychology currently provides. Is trust more of a solid building block of our personality, or is it an unstable trait that is subject to strong fluctuations? What biological and, above all, neuroscientific findings are available to better understand trust in social relationships? How can trust be reliably measured, and what indicators signify trustworthy behavior? The book views trust as a process and identifies characteristics that promote, hinder, or even lead to a complete loss of trust.