R. Chananel wrote the first complete commentary on the Talmud, today embedded in the Vilna edition Talmud page on certain tractates. The commentary only addresses the orders Moed, Nashim and Nezikin, in other words the topics relevant to practice at the time of writing, and some sections have been lost. Some further fragments have been recovered from the Cairo Genizah and are published in B. M. Levin's "Otzar ha-Geonim", and there is now an edition published by Vagshal covering tractate Berachot and order Moed, which also includes the "Sefer ha-Mafteaḥ" of his colleague Nissim Gaon. The commentary presents a paraphrased summary of the main arguments in the gemara, omitting most of the non-legal sections (Aggada). A distinctive feature of the commentary is the presentation of the parallel passages from the Jerusalem Talmud.