The revision I was not able to restore, even though WordPress software indicated that it had been restored, was 5/27/13 10:44.
I have no idea why the system did not work. I am now restoring it manually.
What is displayed on the right or left, when comparing revisions, depends on how one displays the revisions. They should not be identified as right or left, because direction, right or left, depends on what revisions one is comparing. The revisions are identified by time and date. (5/27/13 10:44)
I have no idea how I got into this problem, whether it will trouble me in the future, or appear on other pages. The system is designed to restore revisions, I can achieve that, except for the 5/27/13 10:44 revision of Chapter Two, Hermann Goering. The system works for me on other pages.
I now have the 5/27/13 10:44 revision partially restored manually, and am still working on it. It is slow going, but the only recovering technique I can think of.
The bug seems to be limited to a specific revision of a specific page.