Pseudonym of a cabalist belonging, according to Jellinek, to the school of Isaac the Blind. The works which bear this name are: "Sefer ha-Yiḥud," probably on the Tetragrammaton, quoted by Meïr ibn Gabbai ("'Abodat ha-Ḳodesh," 9th ed., Cracow) and Moses Cordovero ("Pardes," 65th ed., Korez); "Sefer ha-'Iyyun," on the existence and unity, of God, and followed by a mystical prayer in the style of the "Hekalot de Rabbi Neḥunya ben ha-Ḳanah," arranged in the order of the EighteenBenedictions. The "Sefer ha-'Iyyun" was published at Warsaw in 1798, among the "Liḳḳuṭim" of Hai Gaon, the end of the "Sefer ha-'Iyyun" bearing the special title "Sha'are Shamayim." A small fragment which was found embedded in R. Gamaliel's prayer ("Sefer ha-Yiḥud") was published by Jellinek.