I first ran across this book in seminary, and it has only just recently come back into print. (You can find a few copies on Amazon.) When I bought it I could only find a used copy for over $100.00. I would have paid twice that!
I highly recommend it as Derrett is a professor of Oriental Law and does extensive research on the culture and laws of the Jewish people that explain what Jesus' hearers would have understood in his stories and parables.
This is the only resource I have ever found that accurately explains the parable of the dishonest steward. It also talks about the coin in the fish's mouth, the vineyard owner and the tennents, and several more that I can't recall as I type this. 
Really, really worth it and I'd love to add it to my Logos library.
