R. Isaac b. Meir Dueren (second half of 13th century), German halakhic authority on the laws of issur ve-hetter. R. Isaac's surname Dueren derives from the town of that name in Germany. In his youth he studied under R. Tobias b. Elijah of Vienne in France. The period of Dueren's activity has hitherto been uncertain owing to the possibility of his having been confused with other contemporary local scholars of the same name. His date however can now be determined with some precision. Not only does Israel Isserlein state (Pesakim u-Khetavim, no. 215) that R. Meir b. Baruch of Rothenburg is to be regarded as a batrai ("a later authority") compared with Dueren. Dueren is chiefly known for his Sha'arei Dura (Issur ve-Hetter shel Rabbi Yizhak mi-Dura, She'arim mi-Dura, Dura, etc.), which deals with the laws of forbidden food and of menstruant women. This book, based wholly upon the traditions of Germany and France, became the basis of halakhah in this difficult sector, exerting a decisive influence upon all Ashkenazi halakhic authorities after him from the Aguddah of R. Alexander Suslin ha-Kohen through Terumat ha-Deshen of R. Israel Isserlein until Torat Hattat of R. Moses Isserles. The early halakhic authorities guided themselves by the rule that R. Isaac was to be followed in issur ve-hetter even when he was lenient, although the rule did not apply to terefot (Pesakim u-Khetavim, no. 215). Sha'arei Dura was first published in Cracow in 1534. Since then it has been republished many times with the addition of many glosses and commentaries by the greatest talmudists in each generation, among them R. Israel Isserlein, R. Solomon Luria, R. Elijah Loans, and R. Nathan Spiro. These glosses, as well as those of the scholars who preceded R. Israel Isserlein, were sometimes indiscriminately incorporated into the text, so that it is difficult, without the aid of manuscripts, to determine the original content of the book. The book was regarded with such sanctity that R. Hayyim b. Bezalel, brother of R. Judah Loew of Prague, complains about R. Moses Isserles' daring to deviate in his Torat Hattat from the order of Sha'arei Dura. He also wrote tosafot to Gittin and Kiddushin.

בשער: ותהי התחלתו יום כה אלול שנת ד'ש'נ'ה' ורעננה. בראש הספר: הקדמת המעתיק והמגיה ר' אליהו לואנץ. כותב בין השאר: [הגהות] הגאון מוהר"ר שלמה לוריא ... אני המעתיק קראתיו מכונות ... דבריו אלה הם ממהדורא בתרא [מהדורא קמא מקוצרת נדפסה בתוך ספר השערים לר' יצחק מדורא, לובלין שנ"ט, בשם עטרת שלמה] ... ולא רציתי להוסיף על דבריו ... זולת הלכות נדה נתתי להדפיס בקצת חדושי אשר הוספתי משמני ומדבשי ... על-פי וויניציא ש"ח; לובלין [של"ד].