Ethical writer at Worms; flourished from 1460 to 1480. He attended the lectures of Moses ben Eliezer ha-Darshan (Zunz, "Z. G." p. 105), whom he praises in high terms. Isaac wrote in German an ethical and ascetic treatise under the title "Sefer ha-Gan" (Cracow, about 1580). It is divided into seven parts, one for each day in the week. Translated into Hebrew by MosesSaertels, it was subsequently printed, together with Johanan Luria's "Sefer ha-Derakah," in Prague (1597, 1612) and Amsterdam (1663, 1713). The Hebrew translation has been twice rendered into German ("Das Hochgelobte Sefer ha-Gan," Hanau, about 1620; "Das Ist der Teutsch Sefer ha-Gan," Fürth, 1692).