This is definitely a three volume set of books: a text, a workbook and a teacher's manual, that I read through from continuously, and have to the previous 31 yrs. It is among the most significant spiritual messages of our time. The Course combines 21st Century psychology with non-dualistic metaphysics. https://www.youtube.com/channel/UCXpL4OXSmktqlP6_S5p5jIQ