Reb Nachman also wrote "Sefer HaGanuz" ("The Hidden Book") and the "Sefer HaNisraf" ("The Burned Book"), neither of which is extant. Reb Nachman told his disciples that these volumes contained deep mystical insights that few would be able to comprehend. While he dictated the "Sefer HaNisraf" to Reb Noson, the latter said that he did not understand it at all; later he said, "What I do remember is that it spoke about the greatness of the mitzvah of hospitality and preparing the bed for a guest". Reb Nachman never showed the "Sefer HaGanuz" to anyone. In 1808, Reb Nachman burned all the copies of the "Sefer HaGanuz" and the "Sefer Ha-nisraf".