The subtitle is "A Novel of Temeraire" and it does indeed feel almost like a side-story, being restricted in scope, quite removed from the overall plot and at times appearing to lack in content, the author seeming to struggle for inspiration in a few moments. But at least the dragons are still interesting and the amount of human filth was reduced thanks to their very limited contact with others through a large part of the story, so anyone who liked the series so far certainly shouldn't shy away from this book either.