Tony -

I know of one book on the Oral Law, and it is available for free on the Internet, though on a web-site that I do not necessarily endorse. It is titled, "Little Sister" The Oral Law, written by Rabbi Avraham Feld.

I found an Internet reference to another book titled, "To the Source", by Rabbi David Sipper, but I was unable to find any information on it.

UriYosef