Here is Robert Jewett, from the Foreword of “From Paul to Valentinus: Christians at Rome in the First Two Centuries,” © 2003Minneapolis: Fortress Press, (Trans. Michael Steinhauser):
This study is so masterful in its grasp of a vast array of evidence, so solid and innovative in its methodology, and so audacious in conception that it has already become a classic. With encyclopedic thoroughness and objectivity, every possible detail from history and archaeology is presented and evaluated. The treatments of Hermas, Justin, the Valentinians, and dozens of other leaders comprise a virtual monographs within the larger study, developing a variety of methods in assessing social roles and status. Compared with studies by [and he lists 17 such studies by leading scholars and the introductory sections of critical commentaries], and even the recent collection of essays edited by Karl P. Donfried and Peter Richardson, Lampe’s work represents a quantum leap in specificity and comprehensiveness. For those interested in interpreting early Christian literature within its social context, this book opens a new era with ramifications that could transform our understanding of the Christian movement.
Jewett himself has recently written the “Romans” commentary in Fortress Press’s Hermeneia series.