German Talmudist; died in Stryj, Galicia, May 25, 1832. He was a great-grandson of ?ebi Ashkenazi and a pupil of Meshullam Eger. Jacob was ab bet din in Kalisz and afterward in Lissa, and is usually quoted as Jacob of Lissa or Jacob Lisser. Later he returned to Kalisz and lived there for ten years. Jacob wrote: "Ta'alumot ?okmah," commentary on Ecclesiastes (Lemberg, 1804; Dyhernfurth, 1819); "?eror ha-Mor" and "Palge Mayim," commentaries on Canticles and Lamentations, under the general title "Imre Yosher" (ib. 1815 and 1819); the character of all three is homiletic-haggadic. Jacob had intended to write commentaries on the Five Megillot also under this title.
Jacob's importance, however, rests upon the following halakic writings, all of which contain ?iddushim and bi'urim: (1) "Sefer ?awwot Da'at," commentary on Shul?an 'Aruk, Yoreh De'ah, 69-201; the earlier sections of Yoreh De'ah (1-68) are very briefly dealt with in the form of an introduction to the work (Lemberg, 1799; Dyhernfurth, 1810, and often since in editions of the Yoreh De'ah, as the Wilna [1894] ed.). In it the works of earlier commentators are discussed and somewhat pilpulistically developed. (2) "Sefer Me?or ?ayyim," commentary on Shul?an 'Aruk, Ora? ?ayyim, 429 and following, with notes on the commentaries "?ure Zahab" and "Magen Abraham"; the second part contains ?iddushim on Keritot (Zolkiev, 1807; Frankfort-on-the-Oder, 1813; Warsaw, 1825; Dyhernfurth, 1827). (3) "Sefer Netibot ha-Mishpa?," commentary on Shul?an 'Aruk, ?oshen Mishpa?, in two parts (Dyhernfurth, Lemberg; Zolkiev, 1809, 1816; Sudilkov, 1830; and often since in Lemberg editions of Shul?an 'Aruk, ?oshen Mishpa?). (4) "Sefer Torat Gi??in," commentary on Shul?an 'Aruk, Eben ha-'Ezer," 119-155, and ?iddushim on the Talmudic treatise Gi??in (Frankfort-on-the-Oder, 1813; Warsaw, 1815). (5) "Sefer Bet Ya'a?ob," commentary on Shul?an 'Aruk, Eben ha-'Ezer, 66-118, and on the Talmudic treatise Ketubot (Grubeschow, 1823). (6) "Sefer ?ehillat Ya'a?ob," a collection of discussions and notes on several legal points in the Eben ha-'Ezer and Ora? ?ayyim (Lemberg, 1831).
Toward the end of his life Jacob composed a short compendium of dinim, under the title "Derek ha?ayyim" (Zolkiev, 1828; Altona, 1831). This compendium is very popular and was frequently reprinted in the larger Hebrew prayer-books. These dinim are taken either from later exponents of the Law as contained in the works "?ure Zahab," "Magen Abraham," "Peri Megadim," etc., or from his own decisions. The sources from which he borrowed are usually indicated.
Jacob wrote also a commentary on the Pesa? Haggadah under the title "Ma'aseh Nissim," with the text and a short compendium of the Passover ritual ("Ki??ur Dinim"; Zolkiev, 1807, 1835; Minsk, 1816; Dyhernfurth, 1817, and later). After Jacob's death his grandson Naphtali Z. N. Chachamowicz published his "Na?alat Ya'a?ob" (Breslau, 1849), containing sermons on the Pentateuch, halakic ?iddushim, responsa, and his last will.