The Eerdmans Dictionary of Early Judaism is 40% off this month. If you have any interest in understanding the world of Jesus and those who listened him, grab it.
Even if you know your OT very well, you may not be well informed on the 2 - 3 centuries before Christ. This dictionary is a great way to find the information you need on the 2nd temple period.
Before the dictionary articles (A-Z) even begin, you have almost 300 pages of background essays by some of the top scholars on 2nd temple topics which alone justify the purchase price:
- Early Judaism in Modern Scholarship (John J. Collins)
- Jewish History from Alexander to Hadrian (Chris Seeman & Adam Kolman Marshak)
- Judaism in the Land of Israel (James C. VanderKam)
- Judaism in the Diaspora (Erich S. Gruen)
- The Jewish Scriptures: Texts, Versions, Canons (Eugene Ulrich)
- Early Jewish Biblical Interpretation (James L. Kugel)
- Apocrypha and Pseudepigrapha (Loren T. Stuckenbruck)
- Dead Sea Scrolls (Eibert Tigchelaar)
- Early Jewish Literature Written in Greek (Katell Berthelot)
- Archaeology, Papyri, and Inscriptions (Jürgen K. Zangenberg)
- Jews among Greeks and Romans (Miriam Pucci Ben Zeev)
- Early Judaism and Early Christianity (Daniel C. Harlow)
- Early Judaism and Rabbinic Judaism (Lawrence H. Schiffman)
Highly recommended. I find myself using this dictionary several times a month.