Eisenbrauns is having an 80% off sale on the 3rd Edition of The Oxford Dictionary of the Christian Church! It is a pre-order so take advantage of it while you can! This is a good resource and can be useful for all sorts of research or study and dare I say it? sermon prep!
consider too that it is $150 on Amazon!
here is a blurb: Uniquely authoritative and wide-ranging in its scope, The Oxford Dictionary of the Christian Church is the indispensable one-volume reference work on all aspects of the Christian Church. It contains over 6,000 cross-referenced A-Z entries, and offers unrivalled coverage of all aspects of this vast and often complex subject, including theology, churches and denominations, patristic scholarship, the bible, the church calendar and its organization, popes, archbishops, saints, and mystics….
so it seems like a good book for learning a bit more of church history, no?