I have mixed feelings about this book. On the one hand, this is a really important work of New Testament scholarship. DeSilva examines four cultural dynamics (honor, patronage, kinship, and purity) which played a much larger role in ancient mediterranean cultures and the shaping of scripture than most modern Christians realize. I was already somewhat aware of these cultural dynamics, and yet I found deSilva's work to be immensely illuminating. I would highly recommend this book to anyone who regularly teaches from, or studies, the New Testament.
On the other hand, there are a few smaller sections in the book which are of notably lower quality. DeSilva ends his presentation of each theme with suggestions for how modern Christians should incorporate it into their own faith practice. These sections assume without question that the ancient cultural frameworks within which the Bible was written should be normative for modern readers. DeSilva does not address the notoriously thorny task of translating culturally-specific teaching into universal religious truth. To use a couple examples (not from deSilva's book), few modern Christians greet each other with a holy kiss, despite New Testament writers repeatedly instructing Christians to do so. Nor do most western churches require women to wear head coverings in church, despite Paul's clear command to the Corinthians. These are some of the countless expressions of ancient culture which, though they shape the teaching of scripture, modern Christians rightly conclude need not be applied today. DeSilva does not mention the need for these kinds of distinctions. Rather, having just explained how particular biblical themes are culturally-conditioned, deSilva then uncritically applies them to the modern context. At the same time, he avoids mentioning the other, more problematic, applications of these themes, which have historically caused great harm. Much modern scholarship has explored the sociological, psychological, and cognitive implications of purity/impurity, honor/shame, and in-group/out-group thinking, but deSilva considers none of this in his suggestions that we import these concepts form the ancient world into our modern practice. As a result, this book whipsaws between valuable scholarship and uncritical moralizing. I understand the desire of Biblical scholars to make their work practically relevant for their Christian audience, but deSilva has done a better job of it elsewhere, for example in his excellent Introduction to the New Testament.
TL/DR: read this book for the great Biblical scholarship; skip the unscholarly moralizing.