New exciting book!
I've been meaning to write something about Rami Reiner, who was my teacher for one semester at Hebrew U. He wrote a short review (in Sidra 21) of Haym Soloveitchik's Yeinam, in which he develops the idea that Rabbeinu Tam was temperamentally a conservative person, and it was really his nephew, R. Isaac of Dampiere, who had the audacity to carry through the halakhic revolution of Baale ha-Tosafot. Soloveitchik has said that this impression will be overturned by his forthcoming book on wine and halakhah.
Reiner also published a short piece in Alpayim, previewing his very interesting work on the Jewish gravestones found in Wuerzburg. Among other things, he discusses the tombstone of a convert to Judaism, and that of the daughter of R. Yoel of Bonn, the sister of the Raavya, who died in childbirth (important information about members of this family in Simcha's book) .
And finally, in a collection of lectures given at Ben Gurion University, he published a study on the use of Halakhot Gedolot in early Ashkenaz. I haven't finished reading it yet, but it seems to be very good. He has some convincing examples of Rabeinu Gershom rejecting Halakhot Gedolot in favour of his teacher's position.