This volume celebrates the unique contributions of Helmut Koester, who has been a leader for fifty years as scholar, professor, editor, and mentor. Having studied at the universities of Heidelberg and Marburg, Koester was a student of both Gunther Bornkamm and Rudolf Bultmann. He began teaching at Harvard Divinity School in 1958, where he is currently John H. Morison Research Professor of Divinity and Winn Research Professor of Ecclesiastical History. He is the chair of the New Testament Editorial Board of Hermeneia: A Critical and Historical Commentary on the Bible and long-time editor of Harvard Theological Review (1975–1999). Among his numerous publications are Trajectories through Early Christianity (with James M. Robinson); Ancient Christian Gospels; History, Culture, and Religion of the Hellenistic Age; History and Literature of Early Christianity; and The Cities of Paul: Images and Interpretations from the Harvard Archaeology Project (CD-ROM). He was President of the Society of Biblical Literature in 1991 and was awarded an honorary doctorate from Humboldt University (Berlin) in 2006.