His best-known works are, "An Introduction to the Code of Maimonides (Mishneh Torah)", and the more popular anthology, "A Maimonides Reader," as well as "Rabad of Posquieres: A Twelfth-Century Talmudist," which was based on his doctorate work. He was the editor of the "Harvard Studies in Medieval Jewish History and Literature" (in three volumes), won a Guggenheim Fellowship in 1989, and was a fellow of both the American Academy for Jewish Research and the American Academy of Arts and Sciences. According to , Twersky can best be characterized as a "historian of ideas and a researcher of the intellectual history of the Jews," and would presumably have considered himself as such.