An enjoyable first part of a fantasy series - not so much as a single book, though.
When I picked up the book, I was intrigued by the premise: an alternate universe where almost everything is (mostly) similar to ours in the 19th century, except dragons exist, they're sentient and are used for war, and because of this they and their riders very sought after by the armies of most countries and empires.
From the premise, I guessed it would have either been a silly fun romp, but the world building did turn out to be much more deep and well crafted than I would have imagined. The author could have gone with a full blown high fantasy world, but instead she decided to stick to the real world of the time, and she definitely did her research. If the next books will focus a bit more on the other countries and how they fit into this world, or at least on other foreign characters, I will be definitely read more of this series.
However, a few things didn't completely grab me: the main characters, both Temeraire, the dragon, and Laurence, his human rider, aren't really that compelling, at least so far. There are a few elements in the story that I hope will be explored in future books, but for the moment there isn't much of note to them - aside form the fact that they both speak like dapper gentlemen, especially Temeraire. If I had a shot everytime either of them says "pray" instead of "please", I'd need a new liver.
The story itself is a pretty standard "boy and his dragon" kind of plot, not done badly and with some nice twists due to the realpolitiks of this world, but still a bit predictable in some parts. At points the book feels a bit more like a set up for the rest of the series than an enjoyable story of its own. I have a few more thoughts, but I'll hold them back until after I've finished the second book in the series.