Kether Shem Tov - The Crown of the Good Name

Dealing specifically with the Divine Names and Sefirot, this is a deeply mystical text in the Jewish tradition written in the 13th century by the lay preacher Avraham of Cologne. Once it happened that Avraham walked into the synagogue of Shelomoh ibn Adret's father. While he was on the western side of the synagogue, a voice was coming out at the opposite side. They asked it every kind of question, and the voice also known as the "voice of Elijah" answered.