I bought this little paper back book in 1996 for about 14 dollars. I think $55 is a little steep for this brief series of lectures on the influence of Greek and Platonic thought on three early Apologists of the Catholic faith, Justin Martyr, Origen and Clement.
Chadwick's lectures herein are a clear and concise intro into the relationship between human capacity to understand God by way of Reason, as well as the Church's call for faith in the Revealed religion.
As many modern "fundamentalists" make the mistake of arguing that Reason and logic have no place in Christianity, and that people should instead rely completely on blind faith, it becomes important to recognize that the early Church found Greek ethics to be a perfectly compatble part of its theology. Not the ONLY part, but an important part to be sure.
It is out of this early connection that we have the growth of the concept of Natural law, which claims that humans are equipped with Reason in order to clearly understand the elements of which the good and ethical life consists, regardless of the nature of a person's faith.
THis book is a quick read, as it is based upon some lectures Chadwick gave at Oxford in the early 60's. It is not particularly comprehensive. Thus, for $55, I must recommend getting this book at the library, and spending that $55 on another book, like John Finnis' "Natural law and natural rights." Plus a little left over!