What makes trust such a powerful concept? This question has been at the back of my mind for about nine years now while I have been researching trust both in highly abstract terms and in more practical settings. It is with great pleasure and satisfaction, but also with a sense of vulnerability and uncertainty, of course, that I present in this book what I believe to be the most important approaches to understanding trust in the social sciences as well as core original insights into the leap of faith as the essential element at the heart of trust. Young scholars are increasingly discouraged from writing books and advised to focus their efforts on journal articles. Personally, I am glad that people around me have encouraged me to compose and publish this work. The opportunity to develop and describe my scholarly understanding of trust more thoroughly has been immensely valuable to me because in this book I can connect my most recent thoughts with some ideas that I have presented separately in articles and chapters elsewhere. As a result, a bigger picture emerges not just for me, but also for the reader. I have noticed that key inspirations have often come from books rather than articles on trust, which might reflect the fact that trust is a complex topic that does not lend itself well to merely incremental or fragmented contributions. Books, however, can integrate a broad range of ideas and move the field in new directions. The authors whose writings have enabled me to develop my own argument are duly cited in this book. Of those who have encouraged, inspired and assisted me in my work on trust over the years in person, I would like to thank specifically: Mats Alvesson, Reinhard Bachmann, Jens Beckert, Katinka Bijlsma-Frankema, Sandro Castaldo, John Child, Nicole Gillespie, Chris Grey, Rod Kramer, Christel Lane, Frederique Six, Denise Skinner, Jorg Sydow, Malin Tillmar, Antoinette Weibel, Arnold Windeler and Aks Zaheer. Countless others have also helped me through constructive dialogue and exchanges of ideas. I am grateful to all of them and hope that this work provokes further lively discussion to which I already look forward.