This is a great tool I suggest:
The Jewish Encyclopedia- 12 Volumes by Isidore Singer
A discriptive record of the history, religion,literature, and customs of the Jewish people from the earliest times to the present day (1900's)
It is a out of copyright material
for more: http://www.amazon.com/Jewish-Encyclopedia-12-Volumes/dp/B000B68W5S/ref=sr_1_1?ie=UTF8&s=books&qid=1263567932&sr=8-1