Or Adonai (Hebrew: אור אֲדֹנָי), The Light of the Lord, is the primary work of Rabbi Hasdai Crescas (c. 1340 - 1410/1411), a Jewish philosopher. As some Jews prefer to not use even the respectful title Adonai (Lord) other than in prayer (see names of God in Judaism), the book is sometimes called Or Hashem (אור השם) in verbal usage to avoid mentioning even this title of God directly.