Esoteric work describing the process of the future redemption according to the vision of the Vilna Gaon. It was written by Rabbi Hillel Rivlin, a disciple (or according to some — son of a disciple) of the Vilna Gaon. There is some dispute regarding the book, with some questioning the authenticity of the views ascribed to the Gaon or claiming that parts of the work are of later authorship.