I always start from the premise that A Course in Miracles was dictated by Jesus to Helen. There's no doubt about that.
Doubts arise when I begin to read it, and while at first glance it seems sensible and coherent, the more you delve into each phrase and sentence, the more certain concepts don't correspond to the course itself. You realize this because the course fills you with guilt, because it's very difficult to put into practice, based on what the text says. The course itself says you need to experience it. But how can I want to experience guilt? There are many religious institutions that are based on guilt. It certainly works for them, or at least it worked for them, until people got tired of feeling guilty.
The course clearly opposes guilt, even though it can lead you to it.
This is because it was altered. It wasn't Helen or her assistant who did it. The change came later in the editions. And every so often, they continue to edit and change it. It might not work, people might abandon it, or perhaps it's Jesus himself asking you not to read it when you're in this state. Don't confuse the lessons of the course with putting the text into practice.
The associations he makes, at a certain point, leave much to be desired. This is a clear opportunity for you to realize that the man inserted his own words. Perhaps because he thought it was right, perhaps out of jealousy because everyone finds, or rather would find, the solution to their daily problems and, most importantly, would have reached God, or perhaps because he wanted to participate in such an important book. Remember that Jesus said, "This is the gospel I would have liked you to have." Of course, we don't have it, in part.
English isn't a language with many words that can be altered too much, but Spanish does. It had to start somewhere. It's still happening.
Which book should I buy? The one without the supplements is an older edition, and while it has been changed, the changes aren't as significant as in the version with the supplements. There's a book for sale that doesn't have the course's characteristic cross on the cover; don't buy that one. In either case, whether you have one of the two previous versions or not, don't worry, as the corrections will apply to both.
We never had the course exactly as it was taught. While it was known that changes might occur, no one anticipated that the manipulation would be so extensive that people would stop reading it or it would simply become just another self-help book. When in reality, the course itself tells you that you can't help yourself alone.