Children of Dune was the first "end" of the Dune series. At this point there are a lot more books in that series, but this is where the original work stopped.
I enjoyed this more than I thought I would. It's better written than Dune Messiah, and has more content. In it, Paul Atreides' son Leto takes up his destiny. Preborn - having access to all the memories of his ancestors from conception - he finds himself following in his father's footsteps. And going well beyond them.
Some of what Herbert proposes about human nature in Children of Dune is quite interesting. Leto's "solution" is quite unique as well.
While it's still not quite the grabber that Dune itself is, this is a good book, and recommended.