First, let me be clear. This is a good read, with plenty of well-thought out worldbuilding and plenty of fun. You can explain much of this in three words: Napoleonic dragon aviators. If I add that the main dragon character in this series is named Temeraire, you already know whether you want to get this book. But I want to reiterate that the different ways of using dragons as weapons systems, couriers, and even troop transports are well and cleverly done. The analogy to both airplanes and ships is not overstretched, and makes sense in terms of its time and place, had dragons existed. I highly recommend that you buy the book.
But I should be equally clear that I'm a bit weirded by this book's existence in its current form. It is blindingly clear that the author was and is committing alternate world fanfic about Anne McCaffrey's dragons. Hatching and impression are familiar. Bathing in the lake and having young minions is familiar. The separate caste of dragonriders with separate sexual rules is familiar. (And makes little sense in this milieu, as there's apparently no draconic telepathy to drive their human partners to do crazy stuff with the wrong people.) Finally, there's even an analog to the green and gold dragons only accepting female riders. (Apparently all the other female dragons are perfectly okay with male riders. Convenient.)
There are also many significant differences, mind you. This is not a carbon copy. But if one is changing so much, why were these references to McCaffrey not eliminated, or more altered?
Finally, though, I am disturbed by yet another example of the sf/f world's doublethink about fanfic. Anne McCaffrey hated fanfic and was overcontrolling of it when she finally allowed it to exist — but now she's recommending this with a big blurb? What? Stephen King is all against fanfic — but he's recommending this, too?
Seriously, folks, this makes no sense. You can't be all against fanfic one moment, and then playing favorites the next, just because a particular piece is well-written and amuses you. This is exactly the same kind of stuff which got deployed against the fantasy and science fiction genres: "Fantasy and science fiction are childish and bad for literature. But I do like some fantasy and science fiction. How to explain it? I know! I'll call it something else!" Just say, "I don't like most fanfic", and don't stand in the way of the rest.
And yes, if you're stealing huge enough world-building tropes from another writer, you are committing fanfic, whether or not you give it that name. Star Trek owed a ton to Hornblower, and Roddenberry was never shy of saying so. David Drake doesn't hide the debt his RCN series owes to Patrick O'Brien. Warhammer 40K is one big Tolkien alternate world, and everybody knows it. Mary Gentle's Grunts is a Tolkien fanfic, and everybody knows it. There were no orcs or halflings to speak of before Tolkien, guys, and a certain kind of elf is his creation. Being a professional writer and making money from fanfic doesn't change what it is.
But all writing leans on the work of those who went before, and language itself is borrowed from creators of the past and transmitted to creators of the future. I'm not impugning Novik's creativity. This is a darned good piece of original work and professional fanfic, and deserves fame and fortune. Just know what you're getting into, okay?
And watch out for those French dragons hiding up in the sun.