There is a saying that the history of Jewish doctrine runs from 'Moses to Moses'; the second of which is Moses Maimonides. The Guide for the Perplexed is his best known work. It was written as a letter to one of his students, to prepare him to understand the background of the Merkabah (the Chariot of Ezekiel) narrative. In it, Maimonides delves into the most difficult questions of theology and reality itself: Did the universe have a beginning? Will it end? What is the nature of evil?