This book investigates the complex and formative relationship between early Christianity and Judaism, exploring how their divergence shaped the distinct character of Christianity. James D. G. Dunn, a renowned scholar of early Christianity, examines the historical, theological, and social factors that led to the parting of ways between these two closely related religions. The work analyzes key New Testament texts and early Christian writings to understand the theological arguments and practical realities that defined Christianity's evolving identity.

This work is recognized as a significant scholarly contribution to the study of early Christianity and its relationship with Judaism. Scholars often cite Dunn's meticulous research and insightful analysis of primary sources. The book is valued for its nuanced approach to a complex historical and theological subject, offering a detailed account of how Christianity established its unique character through its separation from Judaism. It is considered an essential text for those seeking to understand the foundational period of Christian history.