This is book 4 of the "Skylark" series.

This note contains spoilers for the book.

Triumphant final book of the series; and one of the very few known examples of a "late sequel" (this particular one came 30 years after the preceding material) that works. This is arguably the justification for the whole series -- and it was really pretty well wrapped up at the end of Skylark of Valeron.

DuQuesne finally figures out that ruling Earth isn't for him. I wonder if anybody could do the story of his founding of his empire? I guess David Weber -- at least, he's gotten away with founding or at least re-founding empires with absolute power before.