I like Zondervan's Pictorial Encyclopedia of the Bible over ISBE. My favorite Bible Dictionary is Hasting's Dictionary of the Bible (5 vol.). It was one of the first one's that I purchased. It is old but very good. I have had others, some mentioned above, that are great, like Strong's Cyclopedia and ISBE. As far as topical studies go, I don't think you can get any better than the Thompson Chain-Reference Bible.

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Rev. Andy Eppard
Associate Minister
First Cumberland Presbyterian Church
Springfield, MO