I received my first copy in 1985. Thought then and still think the book is excellent. I have the hard back and the soft cover.
Here is as story to go with:
I traveled out to Oregon for the first time just after getting Arnold's book. While in Southern Oregon I found out Bill Pearl lived there so I called his place to set up a meet with him, as a fan. Bill was his normal cordial and modest self and spent a good amount of time with me. During the course of conversing, I blurted out something like "Hey, have you seen or read Arnold's Encyclopedia?". I will never forget Bill's response it went something like "Yeah, I have seen it, it is almost an exact copy of my 'Keys to the Inner Universe', only not as complete."
Man, did I ever feel like a dumba**!!! I had checked out Bill's "Keys" about 6-7 months before, I felt like running out of the room. Bill was just stating the truth, Keys is much more complete.