So, I've now discovered that there are two other books in the series I had no idea existed! "Children of the Mind" was a fourth book in the series, a sequel; "Shadow of the Hegemon," out just this month, is more of a sequel to "Ender's Shadow" but seems also to tie things together.
So, of course, they're both now on my Amazon.com wishlist. :-)
And now, back to the re-reading of "Ender's Game" that prompted my curious visit to Amazon.