KOL BO (Heb. כָּל בּוֹ; "everything within"), an anonymous work containing both halakhic rulings as well as, at times, explanations of halakhot, arranged in accordance with the subject matter. The book was written at the end of the 13th or the beginning of the 14th century. The identity of its author and its relation to the Orḥot Ḥayyim (on OḤ, Florence, 1750–51; on YD, ed. by M. Schlesinger, 1899–1902) of *Aaron b. Jacob ha–Kohen of Lunel are very complicated problems that have not yet been resolved. The fact that both books cover the same material but that the Orḥot Ḥayyim contains additional and more abundant halakhic material than the Kol Bo has given rise to the view that the Kol Bo is a later abridgment of the Orḥot Ḥayyim (thus Joseph Caro, Ḥ.J.D. Azulai, and others). However, the arrangement of the material in the two books does not support this view. The Orḥot Ḥayyim is much more systematic than the Kol Bo and it is difficult to explain the latter's arrangements in its present form; nor can any reasonable explanation be given for the manner of its abridgment, if it is indeed such. M. Schlesinger, who edited the second part of the Orḥot Ḥayyim, also subscribed to the above view (see his introduction) and added nothing new to previous arguments. An attempt has been made to identify the author with Shemariah b. Simḥah, the grandson of Samuel Schlettstadt (see his pamphlet published in I.A. Benjacob's Devarim Attikin, 2 (1846), which Zunz followed), but for this opinion, too, there is no basis, and the author remains unknown. The view of Benjacob and S.D. Luzzatto appears to be close to the truth, namely, that the Kol Bo is the first edition of the Orḥot Ḥayyim and is by the same author, Aaron b. Jacob ha-Kohen. In any event, the Kol Bo in the extant text undoubtedly preceded the Orḥot Ḥayyim. It is probable that it represents the first stages of the text of the Orḥot Ḥayyim and is earlier than the versions in the three known manuscripts of the Orḥot Ḥayyim (the Ms. from which Part II was published, Jews' College, London, and Ms. Moscow, Guenzburg).
Kol Bo contains 148 sections embracing the following subjects: blessings, prayer, the synagogue, the meal, Sabbath and festivals, marriage, monetary matters, *niddah, vows and oaths, halakhot relevant to Ereẓ Israel, forbidden foods and *issur ve-hetter, mezuzah, the redemption of the first-born son and the firstborn of an ass, visiting the sick, mourning, the takkanot of R. *Gershom and others. Included in this anthology were also collections of laws from various works such as the Even ha-Roshah of *Eliezer b. Nathan; laws from the Tashbeẓ of Simeon b. Ẓemaḥ *Duran; from the Sefer Mitzvot Katan of *Isaac b. Joseph of Corbeil; from *Perez b. Elijah of Corbeil; Isaac, author of the Sefer ha-Menahel; *Baruch b. Isaac of Worms, author of the Sefer ha-Terumah; and various responsa. The book is chiefly based upon *Maimonides' Mishneh Torah, combined with and having additions from the rulings of the scholars of Germany, France, and Provence. Few of the rulings of Spanish scholars are cited (as against the Orḥot Ḥayyim which adds many statements of such Spanish scholars as *Naḥmanides, Solomon b. Abraham *Adret, Yom Tov b. Abraham *Ishbili, and others). The anthology contains much material from various books, not all of which are extant today. With the discovery and publication of the Sefer ha-Mikhtam (ed. by A. Sofer, 1959) of *David b. Levi of Narbonne, the Sefer ha-Mahkim (ed. by J. Freimann in Ha-Eshkol, 6 (1909)) of Nathan b. Judah, and the Sefer ha-Minhagot (in S. Assaf, Sifram shel Rishonim (1935)) of *Asher b. Saul of Lunel, it has become evident that a large part of the Kol Bo was taken from them, even though this fact is not indicated there. It is possible to conjecture that the original material in the Kol Bo is negligible, and that almost all of it was taken from various sources. It was first printed in Naples in 1490–91. The one known manuscript of it in the Guenzburg Collection, Moscow, may well be a copy of the printed edition.
Azulai, 1 (1852), 9:130; 2 (1852), 33:14; Benjacob, Oẓar, 51:984, 239:118; S.D. Luzzatto, in: Meged Yeraḥim, 1 (1855), 5–10; idem, Iggerot Shadal, 8 (1892), 1232:562; Zunz, Ritus, 31f., 179f.; H. Gross, in: MGWJ, 18 (1869), 433–50, 531–41; Gross, Gal Jud, 290, 420; S.M. Chones, Toledot ha-Posekim (1910), 23, 303; Aaron ha-Kohen of Lunel, Orḥot Ḥayyim, pt. 2, ed. by M. Schlesinger, 1 (1902), introd.; J. Freimann, in: Ha-Eshkol, 6 (1909), 107–9.