This collection of essays is partly the product of a symposium that took place at Humboldt University, Berlin in July 2010. It was supplemented by other articles which contributed further relevant aspects to the overall topic. The aim of the conference was to explore the longstanding conundrum of the rapid rise and growth of Christianity in the first three centuries CE. This well-studied question finds a special home in the city of Berlin where, at the beginning of the last century, Adolf von Harnack, Professor at Friedrich Wilhelms University (today Humboldt University) Berlin carried out what was arguably its most famous treatment. According to Harnack, early Christian history began in the missionary activity of contemporary Judaism. The movement spread as the result of a combination of deliberate syncretism with a measure of simplicity in the cultural and political unity of the Roman Empire. Over the past thirty years, scholars such as Ramsey MacMullen and Rodney Stark have questioned some of Harnack's conclusions. Arising from outside of the field of New Testament Studies (Ancient History and Sociology of Religion, respectively), both MacMullen's and Stark's approach remained at some distance from specialist understandings of, for example, complex theological and rhetorical aspects of early Christian texts. Therefore, in the wake of these important studies, a variety of new strategies have emerged taking these and other vital concerns into account. The essays in this volume represent these assorted approaches. Methodological rigor is the only unambiguous theme running throughout this otherwise diverse collection. The essays are collected under two broad sub-headings: Cultural Milieu and Texts. Topics treated include Paul, Jesus and the Gospels, other New Testament texts, the Apocryphal Acts, and the expansion of Christianity in the second and third centuries.