(Larry Hurtado): For the study of Christian origins, familiarity with the ancient Jewish context (or matrix) is crucial. So, all of us will be grateful for a recently published major reference work: The Eerdmans Dictionary of Early Judaism, ed. John J. Collins and Daniel C. Harlow (Grand Rapids: Eerdmans, 2010).
It’s massive in size (xxxviii + 1360 pp., 19 x 25 cm), featuring a combination of 13 themed essays and several hundred entries (alphabetically arranged) by a galaxy of scholars of international provenances. Each of the major essays and the entries has a select bibliography. There is an impressively broad range of topics addressed in the entries. I wrote the entries on “mediator figures” (pp. 926-29) and “monotheism (961-64).
Considering the breadth of coverage, the quality of contributors, and overall quality of the editing and publication format, I’d say this is now probably the essential reference work on ancient Judaism.