Topical

Walter Wink - Engaging the PowersA powerful and engaging look at spiritual powers and warfare. This is a must read on the principalities and powers.Watchman Nee - Sit, Walk, StandThis is devotional material based on three of the imperatives in Ephesians. This book challenged me spiritually and is one that I will definitely read a few more times.

Commentaries

Ernest Best - A Critical and Exegetical Commentary on Ephesians (International Critical Commentary)A pricey but extremely helpful commentary on Ephesians. There are a few other options that are nearly as good without spending this much money. This one and the Word commentary below will require some knowledge of Greek to be beneficial.F.F. Bruce - The Epistles to the Colossians, to Philemon and to the Ephesians (NICNT)Bruce's commentaries in the NICNT commentary series are exceptional and ones that I turn to over and over again. I would go to O'Brien and Witherington before going to Bruce and definitely before spending the money on Best.Andrew Lincoln - Ephesians (Word Biblical commentary)This is considered to be one of the best in the WBC series. I haven't personally used it to any great length but I keep it on hand because of its reputation and because I often use Word Biblical commentaries or the New International Greek Testament Commentaries if I have question on the original languages.Ralph Martin - Ephesians, Colossians and Philemon (Interpretation)This commentary is geared for preachers and teachers and would make a great recommendation for a Bible class teacher looking for resources to assist them in their preparation.Peter O'Brien - The Letter to the Epheisans (Pillar)This is my favorite commentary on Ephesians because of its balance of being thorough and yet highly readable/understandable. If I had to pick one commentary for Ephesians this would be the one.Ben Witherington - The Letters to Philemon, Colossians and the Ephesians: A Socio-Rhetorical CommentaryThis is probably my second favorite after O'Brien and just before Bruce. Definitely one you want to consult if you are studying Ephesians.