Sefer Isur ve-heter (What is forbidden and permitted) is a treatise on Jewish dietary laws written by Yonah Ashkenazi, thought to be the son of Rabbi Israel of Regensburg, a student of Rabbi Israel Isserline. (This work is sometimes erroneously attributed to the Catalan rabbi Yonah Gerondi , d. 1264).

This copy of Isur ve-heter was printed in 1555 and is the earliest edition of the work. The YIVO Library also has later editions published in the 18th and 19th centuries. The 1555 edition was printed in Ferrara, Italy, by Avraham Usque, during a short period (lasting only a few years) in the 16th century when Jews were permitted to publish books in the city.

The anchored globe in the center of the illustration is framed with a verse from Isaiah (40:31): “But they that wait for the Lord shall renew their strength; they shall mount up with wings as eagles; they shall run, and not be weary; they shall walk, and not faint.” The banner wrapped around the anchor is a line from Psalms 130: “I wait for the LORD, my soul doth wait, and in His word do I hope.”

Like many of the rare books in YIVO’s collection, Isur ve-heter contains stamps and inscriptions that attest to the many hands it passed through before ending up in the YIVO Library in New York. In addition to the stamp identifying it as being from the Strashun Library, the book also bears the stamp (left) of Rabbi Benzion Ettlinger, the son of Rabbi Jacob Ettlinger, the Chief Rabbi of Altona (1798-1871), a noted leader of Orthodox Judaism and early opponent of Reform Judaism.

Some time between the 16th and 20th centuries, a page of the book became damaged and someone repaired it with a hand-lettered patch.