Notes on the Parables of Our Lord by Richard Chenevix Trench.
This is an excellent classic treatment of the Parables by R.C. Trench. You will not find a more outstanding treatment of the parables than Trench’s. He quotes many books on the Parables available in his day, and his work is a classic by which to judge all other works. Whether you agree with Trench or not, you should check his interpretation before making a final decision on an interpretation on a parable passage.