Ritba is considered among the great Sephardic Talmudic sages. A student of R. Aaron ha-Levi of Barcelona and R. Solomon b. Abraham Adret (Rashba), Ritba was recognized as a great scholar in his youth. Even during the lifetime of his teachers, questions were addressed to him for he was regarded as among the leading Spanish rabbis. After the death of his teachers, he was regarded by Spanish Jewry as its spiritual leader. When the community of Daroca introduced certain decrees, it was stated that this was done “in the name of R. Asher [b. Jehiel] and in that of R. Yom Tov b. al-Ishbili.” His bet din was referred to by contemporary rabbis as”the great and excellent bet din.” Although he authored other works, Ritba’s reputation rests upon his novellae to the Talmud, Hiddushei ha-Ritba, which he apparently began writing from the direct dictation of his teacher R. Aaron ha-Levi.

When writing his hiddushim Ritba he realized that the work would be inordinately long, deciding therefore, to make an abbreviated version. There is even a possibility that he wrote a third version to some tractates. As a result, his novellae to different tractates are of different types and not always of the same quality. It is sometimes difficult to identify them with certainty. His novellae are, in general, very rich in early source material: tosafistic, Spanish, Provencal, and geonic, and display a considerable originality, though he is very much under the influence of his two great teachers.

R. Isaiah b. Mali Trani (the Elder; c. 1200–before 1260), early Italian halakhist, scion of a well-known rabbinic and scholarly family. Born in Trani, he is mainly known as the author of extensive commentaries and pesakim ("decisions") on the Talmud. R. Isaiah was a pupil of R. Simhah of Speier and kept in contact with German scholars. His responsa are to be found in the Or Zaru'a of R. Isaac b. Moses of Vienna, who greatly esteemed him. He traveled in the Mediterranean countries, spending some time in Greece and in Erez Israel. Among the scholars whom he quotes mention should be made of R. Baruch "of Greece" while R. Zedekiah b. Abraham Anav, author of Shibbolei ha-Leket, quotes him extensively.

R. Isaiah's works cover a wide range. They include: (1) Pesakim on the Talmud, containing a summary of the subject under discussion, along the lines of Alfasi, with additional comments on unresolved difficulties and a final decision on the conflicting views in the manner of Hananel b. Hushi'el. The following pesakim have been published: on Berakhot and Shabbat (1964); on Eruvin, Pesahim, Yoma, and Sukkah (1966); on Sukkah alone in Sam Hayyim (Leghorn, 1801); on Bezah (in Mahaneh David, 1889, wrongly described as Tosafot Rid); on Rosh Ha-Shanah, Ta'anit and Hagigah (in Oholei Yizhak, Leghorn, 1821); on Yevamot (called Tosafot Rid, 1931); on Ketubbot and Gittin (in margin of TB, Vilna edition, wrongly described as Tosafot Rid); on Kiddushin (1965); on Makkot (in: Talpioth, 8, 1963); on Horayot (ibid., 9, 1965); on Hullin (first chapter, in Ha-Segullah, 1940), and on Niddah (1963). His pesakim on the Halakhot Ketannot have also been published (Leghorn, 1801). The remainder are still in manuscript. (2) Sefer ha-Makhri'a (Leghorn, 1779) deals principally with important halakhot in regard to which the codifiers were in dispute, and which Isaiah attempts to resolve. (3) Sefer ha-Leket (not extant) is similar in nature to ha-Makhri'a. (4) Tosafot Rid, novellae to the Talmud. Extant are his novellae to the tractates: Shabbat, Eruvin, Pesahim, Yoma, Sukkah, Bezah, Rosh Ha-Shanah, Megillah, Hagigah, Mo'ed Katan, Nedarim, Nazir, Bava Kamma, Bava Mezi'a, Bava Batra, Avodah Zarah, and Niddah (Lemberg, 1862–68; new edition in preparation partly printed); Kiddushin (Sabionetta, 1553, and subsequent editions, the latest, New York, 1965); Ta'anit (at end of Sefer ha-Makhri'a). Tosafot Rid was compiled in several "editions" in the form of pamphlets in which Isaiah retracted or supplemented his previous statements. The exact relationship between this book and his pesakim has not been established, as much of the material is common to both and in addition the printers added to the confusion. (5) Responsa (1967). (6) Commentary on the Pentateuch. Extracts from this commentary were published by R. H. J. D. Azulai in his Penei David (Leghorn, 1792). The commentaries on the other books of the Bible, published under his name in Jerusalem in 1959, are apparently to be ascribed to his grandson. (7) Piyyutim. R. Isaiah was an independent thinker with considerable originality of approach and with a critical attitude to the opinions of his predecessors. Occasionally he sharply rejects the teachings of geonim, such as R. Hai Gaon and R. Samuel b. Hophni, and of other distinguished predecessors. He even criticizes his own works, commenting, "All that I have written is valueless (hevel)." He is not awed by authority, and is concerned only with examination of the source material. His books are distinguished by clarity of explanation, careful choice of correct readings, and methodological approach to talmudic principles and lines of reasoning.

ספירת-דפים משובשת. בסוף הספר התנצלות המגיהים: ר' שלמה זלמן ב"ר מתתי' זצ"ל דיינא ק"ק ליסא ועתה מתגורר בברלין ור' נפתלי צבי יכונה הירש ב"ר יעקב הלוי זלה"ה מגניזן.

הסכמות: ר' יחיאל מיכל [חסיד] ב"ר יהודא ליב [דרשן מפראג], ברלין, כב כסליו תע"ה; ר' אהרן [ב"ר יצחק בנימן וואלף], פרנקפורט דאדר, חיי שרה [תע"ה].