In The Coming of the Comforter: When, Where, and to Whom?, Studies on the Rise of Islam and Various Other Topics in Memory of John Wansbrough, a posthumous Festschrift edited by Carlos Segovia and Basil Lourié.
About this book the publisher tells us:
John Wansbrough is famous for his pioneering studies on the "sectarian milieu" out of which Islam emerged. In his view, Islam grew out of different - albeit rather marginal - Jewish and Christian traditions whose intertwinings deserve being studied. In the present volume, which is dedicated to Wansbrough's memory, specialists in Islamic studies and students of the Jewish and early Christian traditions out of which Islam presumably arose summarise Wansbrough's achievements in the past thirty years. The volume also goes a step further by setting forth new landmarks for the study of the traditions implied in Wansbrough's aforementioned concept of the "sectarian milieu" from which Islam emerged, perhaps later than is commonly assumed and in a rather unclear, even ambiguous way.You may peruse the table of contents here.