Kasher's major work, Torah Sheleimah, is divided into two parts. The first part is the encyclopedia, the first work to publish all of the Written Law and the Oral Teachings side by side. Kasher published from manuscript form several previously unknown midrashic works such as the Midrash Teiman. The latter part consists of the extensive annotations and addendum in which he used his awareness of variant texts as well as his almost encyclopedic knowledge in all Jewish works to clarify many obscure points in the Talmud and the Rambam's commentary. The first volume of Torah Sheleimah was published in Jerusalem in 1927 and included 352 entries to the first chapter of Bereishit. The 38th volume was published in his lifetime and included Parshat Beha'alotcha. The 39th volume was published posthumously by his son-in-law Dr. Rabbi Aaron Greenbaum and includes a short biography. The 40th volume includes an expanded biography and full list of his works. To date, 45 volumes have been printed covering the first four chumashim.
Other activities
He was the driving force behind the 25-volume Torah journal "Noam", and wrote many of the articles. His son Moshe edited its 25 volumes which appeared between 1958 and 1984. Another work, Gemara Shelemah, which was to have discussed and compared variant texts of the Talmud, was never completed save for Tractate Pesachim.
He argued against the "Lieberman clause" as a solution to the problem of agunahs – see Get
In response to the establishment of the State of Israel, he advocated the drinking of a 5th cup at the Passover Seder. His request to the Chief Rabbinate that it be officially instituted was dismissed.
Published worksIntroduction to Torah Sheleimah Volume 40
Torah Sheleimah — an encyclopedic work on the Torah
HaTekufah HaGedolah — a treatise explaining the meaning of our times according to Judaism, and which was a rebuttal to the Satmar Rav's work, Yoel Moshe, in which the Satmar Rav explains his view that Zionism was against halacha.
Ha'odom Al Hayarei'ach — a discussion of the theological and legal issues involved when the moon was explored
HaMechilta DeRashbi VeHaRambam — a discussion of the relationship between the Rambam's Mishneh Torah and a recently published midrash.
Divrei Menachem — responsa from many of the foremost scholars of the day, including the Rogatchover Gaon and the Klei Chemda. 4 volumes were published; in 1977, 19080, 1981 and 1983.
Haggada Sheleimah — an encyclopedic work on the Pesach Haggada
Haggadat Pessach EretzYisraelit - the Kasher Haggada - with a short running explanation. This was one of the first haggadot to be translated into English with commentary.
Haggda Leil Shimurim - includes about 100 "Pesach-related" sayings from the 5 sages who are mentioned in the Haggada.
Arab'at Haroim discussing the opinions of 4 earlier Rabbis about the upcoming redemption
Kav Hata'arich - discusses the date line in Jewish law. It includes full color maps and the 3 major opinions on the subject as well as his own, a 4th opinion.
Sefer Shma Yisrael and includes about 500 sayings on the first chapter of the Shma.