As always, if you’re new to the field of Early Church study, Chadwick’s paperback book is a good place to start. It manages to whiz through the people and events of the fifth century christological controversy in a mere, but rather dense, 20 pages.

If you want to go a bit deeper, it’s time to pick up Kelly’s standard Early Church textbook which covers the controversy in Chapter 12 “The Christological Settlement”. However, it’s worth reading Chapter 11 too (“Fourth-Century Christology”) which provides the background to the debate and a sketch of the different Christological positions (Alexandrian & Antiochene) which are characteristically represented as starting from different perspectives and coming to blows in the 5th century.

This book was printed by several different publishers and was available in both paperback and hardback, although it now seems to be out of print (although Amazon have a new (2nd) edition listed as coming out in September 2007). You should be able to find several copies second-hand on Abebooks from about £15 upwards.

If you’ve followed the events and arguments outlined in Kelly and/or Young’s books (above), McGuckin’s book is a superb follow-on. Quite simply this is the single best book to get on the fifth century controversy, and now mercifully available in paperback (instead of just the £90 + hardback version which I had to cough up for!).

This scholarly work presents an excellent and balanced perspective on the controversy from both sides (from Nestorius' side as well as Cyril's), showing the objections of each side to the Christology of the other. In particular, McGuckin presents a more sympathetic portrayal of Cyril and his motives than the traditional thumbnail sketch of Cyril as a scheming & sneaky ecclesiastical politician which is usually given.

As always with McGuckin's work, it's very readable & accessible for the non-specialist to a large extent. It does get into quite some technical detail about the precise meaning of certain Greek words used in the debate and their exact meaning, but you don't have to wrestle with this aspect if you don't want to. This is the standard advanced undergraduate/ post-graduate text book on the topic. But don't let that put you off!

Besides Cyril’s important 2nd and 3rd letters, McGuckin also usefully provides translations of some of Cyril’s other works which are well worth reading - these include his Letter to the Monks of Egypt, the Explanation of the Twelve Chapters (Anathemas) and the Scholia on the Incarnation of the Only Begotten .

Amazon has it listed as “special order”, but you should be easily able to get a new or like new copy from an Amazon Marketplace Seller. You’ll probably find that Blackwell’s bookshop also keeps it in stock.

In the past, because of his role in the Christological Controversy, Cyril has been studied almost exclusively for this aspect of his thought. This book, however, contains a welcome collection of essays by a number of excellent scholars which examine other aspects of Cyril’s theology. For a better review than I could manage, see this article in the Anglican Theological Review of Summer 2004, by Peter Widdicombe.

This book is the standard collection of (English translations of) Early Church source documents for this period. With regard to Cyril’s writings, you’ll find Cyril's 2nd letter to Nestorius and Cyril's 3rd letter to Nestorius (including the “Twelve Anathemas”).

In addition there is much other interesting correspondence on the same topic (e.g. Nestorius’ reply to Cyril’s 2nd letter, Cyril’s defence of his acceptance of the Formula of Reunion). You’ll also find source documents concerning the important council of Chalcedon including the Chalcedonian Definition of the Faith (i.e. the Creed produced at Chalcedon).

Russell's book contains some good-sized chunks of English translations from Cyril's texts which were not directly connected with the Nestorian controversy (e.g. his commentaries on Isaiah and John’s Gospel) - yes, Cyril did write on other topics too! Russell’s book therefore enables you to get a feel for Cyril as an exegete, rather than just a rabid Nestorian-basher. There's also a very useful introduction into Cyril's life and background - recommended.

If you want a single (small) book containing Cyril's perspective on the person of Christ (strongly contrasted with Nestorius’ position) this is it. The text takes the form of a dialogue between two friends with Cyril pulling the strings and putting words in the mouths of both participants, to show the folly of the Nestorian position!  There's also a (sizeable) introduction to the controversy as well as to Cyril himself.