Description:I used Dunn's book to help prepare for my Master's thesis, which is a translation of Tertullian's De anima ("On the Soul"). Dunn's introductory material gives a pretty good introduction to modern thinking on Tertullian. He basically follows T.D. Barnes' somewhat controversial views. There's nothing wrong with that -- Dunn both presents Barnes' views somewhat more clearly than does Barnes himself, and Dunn builds on other scholarship that wasn't available to Barnes in the late 70's -- like the rhetorical influences on Tertullian.
Speaking as someone who is very familiar with Tertullian's Latin, I found Dunn's translations to be quite good. I have a higher opinion of the translations of Tertullian in the Ante-Nicene Fathers series than did a previous commentator. That said, Dunn gives us translations of some of Tertullian's work that is not available in English and he does a good job of it.
I found this book quite helpful for my thesis, and recommend it for anyone who wants to learn about a truly fascinating writer who lived in a very interesting period of history.