There are at least 3 topics that come to mind:
1) IDOLATRY: The Gemarah states that in Abrohoms time the tractate dealing
with Idolatry was 400 pages long! Apparently the prevalance of idolatry
increased the questions relating to it!
2) MONETARY LAW: Obviously, laws concerning theft, commerce, bailees etc
were learned. In fact theft is one of the 7 Noachide laws and therefore all
monetary law was studied. The codes of Hamurabi may have come from here.
3) HILCHOTH NIDDAH (Laws of family purity): Rabbi Manis Friedman in his
wonderful book: Does Anyone Blush Anymore: Reclaiming sexuality, intimacy
and modesty in a promiscuous world--remarks that the cycle of separation
and intimacy created by the Biblical Niddah laws are common in many
cultures and part of any healthy marriage. It therefore seems reasonable
that they could have studied these laws (cf Rashi Gen 18:9-12)
I will use these 3 examples to answer Baruch Cohen's sons question: >>How
come they did not write down and record any of their Torah that was
discussed so that we could benefit from it>>
1) Well indeed I agree with Yehuda that we have a great loss in not having
Abrohom's Idolatry tractate. Alternately I could answer that Idolatry is
not as prevalant today and it suffices to have the small masechtah (
tractate) we have.
2) The monetary laws of Noach were fully developed and then superceded by
the Torah laws. So today we study only Torah law.
3) It is not clear if they did learn Niddah there. But even if they did:
Niddah in Shem Vever's time was simply a fulfillment of being kind to your
neighbor(in this case your wife) while today it is a full fledged Biblical
I hope this answer's Yehuda's question.(He will grow up with a keen legal
mind like his father).
Russell Jay Hendel; Ph.d.,ASA, RHendel @ MCS Drexel Edu