This is actually a 3 volume list of books: a text, a workbook and a Instructor's handbook, that I go through from consistently, and have for the earlier 31 years. It is probably the most important spiritual messages of our time. The Course combines 21st Century psychology with non-dualistic metaphysics. https://www.youtube.com/channel/UCXpL4OXSmktqlP6_S5p5jIQ