Among these were a Pentateuch with haftarot and Rashi (1828; his le'azim translated into German), Sabbath prayers (1828), and piyyutim (Torat Emet-Tikkun Soferim, 1827, repr. 1937); Amarot Tehorot (biblical books with Dutch translation, 1862/63; also Job, with M. S. Polak, 1844); a mahzor (18572), with commentary in Hebrew and Judeo-German and another edition with Dutch translation (with M. L. van Ameringen, 18502); Areshet Sefatayim (196023), a siddur; a Passover Haggadah (19309); Ezrat ha-Sofer (1866), a tikkun; and Sefer Hayyim la-Nefesh (1867). He also edited orders of service for Purim (1857), circumcision (1878), and the seventh of Adar (death of Moses; 1851), Kinot (1868) and Selihot (1869). Polak published a small Hebrew-Dutch dictionary, Divrei Kodesh, with S. E. Heigmans, in 18572. Among his other works were: Hukkei Ha-Elohim (1841, 1883), on the 613 commandments; a translation with commentary of Josippon (1868, with van Ameringen); an edition of a manuscript he discovered of Judah ibn Balam's Sha'ar Ta'amei Sefarim Emet on the accents of Psalms, Proverbs, and Job (1858); and an enlarged edition of Abraham Bedersi's (Bedarshi's) dictionary of Hebrew synonyms (1865). Polak completed H. A. Wagenaar's biography of Jacob Emden (1868), and annotated Menahem Mann b. Solomon's She'erit Yisrael (with L. Goudsmit, 1855), with notes on the history of Dutch Jewry. He also wrote Hebrew poetry and translated Dutch works into Hebrew (Ha-Poret, 1836; Halikhot Kedem, 1847; Ben Gorni, 1851). In addition, he wrote a biography of the Dutch Hebrew poet D. Franco-Mendes and published letters and essays by S. Dubno, J. S. Reggio, S. L. Rapoport, and S. D. Luzzatto, maintaining contact with some of them. Among his bibliographical work is Me'ir Einayim (1864) a catalog of the M. L. Jacobson and M. B. Rubens collections in Amsterdam Hok Shelomo (1857) and catalogs of S. B. Rubens' collections in Amsterdam (1864).