Is there a complete chapter in any of Joel’s books on “illusions”?

Oh yes, I think a great many of them. One of the very good ones is a chapter in Conscious Union with God called “The Nature of Error”. Another chapter, or chapters, that give you the essence of it all are really the first four chapters, in particularly the fourth chapter, of Realization of Oneness. And I’ve always thought that “What Did Hinder You” in The Art of Spiritual Healing is a classic on that subject. Of course, you’ll find something about illusion on almost every page, too.