The Working Group on Toleration has set itself the daunting task of producing works to answer questions on what toleration is and how it has developed and is practiced in various societies, as well as what contributes to its creation and its breakdown. The group’s primary focus has been the development of a source book on toleration from different traditions around the world, spanning some two and a half millennia between roughly 400 BC and the modern era. Overall, the volume will be presented as a conversation, organized temporally between various regions and cultures. This conversation will reveal the highly diverse origins of toleration and the different contributions various cultures have made to our understanding of toleration over time. We have confidence that this volume, which has no peer in scale and range, will become a classic.