The Building Bridges Seminar, a gathering of scholar-practitioners of Islam and Christianity, has been convened annually since 2002 for the purpose of deep study of scripture and other texts carefully selected for their pertinence to the year's chosen theme. This book provides a record of the proceedings of the fifteenth such seminar, which met in and near Washington, DC, May 6-10, 2016. Lucinda Mosher begins the volume with a retrospective on the first fifteen years of Building Bridges, providing a context for the model of vigorous and respectful dialogue that characterizes the initiative.  Christian scholars such as Richard Bauckham and Christoph Schwobel and Muslim scholars such as Asma Afsaruddin and Martin Nguyen the explore the contours of monotheism as a theological question.  In addition, the book analyzes texts from the two traditions, featuring reflections by Sajjad Rizvi and Janet Soskice and others on affirming the unity of God. Lucinda Mosher concludes the volume with an insider's look at the deliberations and discussions among participants.