When David Acer asked me for my top 10 magic books, for a column he wrote for Genii a few years ago, I included "Jennings '67" among my 10. David wrote to me to ask if I was sure I hadn't made a mistake. I assured him I hadn't.
"Jennings '67" is, for me, the most satisfying description of the magic of I man I greatly admired. The developmental thinking in the successive treatments of "Invisible Palm Aces" is of inestimable value to the serious card student.
Richard managed some of his best descriptive writing in that book, capturing the nuances that Mike Maxwell left out of the (also invaluable) "Classic Magic of LJ" book. If you are able to re-read "Classic Magic" in light of these nuances, I believe you can get a little closer to what Jennings had in mind with those effects.
You must bear in mind that the book is controversial, in that both Jennings and Bruce Cervon claim authorship of the "Invisible Palm" routine. In very pleasant e-mail conversations with Bruce Cervon, I explained that what Richard had written in "Jennings '67" was Larry's version of the history, not necessarily "The Truth," as if that might ever be attainable. (Ref: "Rashomon.")
By the way, David Acer's column of top 10 books had choices from more than a dozen magicians. I forget which issue it's in, but if you haven't read it, it is one of the back-issue Geniis you might consider purchasing.