Kasher is primarily known as a prolific author. Among his works is Torah Shelemah, a compendium of sources on each verse of the Torah. More than 40 volumes of the work have appeared.. He was also the author of Haggadah Shelemah, which quotes numerous sources related to the Passover Haggadah, and Gemara Shelemah, a comprehensive source for the Talmud, though only his commentary on a few pages of the tractate Pesahim has appeared in print. His Ha-Tekufah ha-Gedolah, published in 1982, deals with the modern era, expressing the view that this is "the beginning of the redemption." He has also done seminal work on the international dateline as it affects Jewish law and was co-author (with J. Mandelbaum) of SareĢ ha-Elef, dealing with all the great Torah authorities who lived in the thousand years between 500 and 1500 CE. He was the founder (1968) and first editor of Noam, a yearly publication which presents articles by prominent rabbinical authorities on current issues.