Strangeness and unexpected results paint your mind with sand and stars.
I had all but the last 2 Frank Herbert Dune books, so I bought this with Heretics of Dune. As far as end caps go, this is a very strange and unexpected conclusion to the Dune Saga. It has the wonderfully descriptive imagery of all F.H.'s previous Dune books and perhaps even more emotional content with regards to that imagery. This becomes a powerful, if a bit confounding, plot device and clues us in to the overarching plans of the Bene Gesserit with respect to the Leto II's (the Tyrant!) Golden Path and what that entails for humanity at large.
A few things did not happen that I really wished would, and some things happened that I really wished wouldn't, but c'est la guerre, n'est ce pas?
Many things go unanswered, or do they? I can't decide yet, it may take another read. But in retrospect it is an appropriate end to the saga, and if you read it you will understand why much better. Though the last chapter is indeed the strangest part of the book and it's reasons for being included are not entirely clear to me...yet. While not a mystery, the suggestions and innuendos that Herbert constantly employs require highly active brain processes to unveil, perhaps you should try some spice before reading it!