It's the Napoleonic wars, with dragons. Most of them don't breathe fire, or the Navy would be gone in a, um, flash. Furthermore, they're intelligent, and born speaking English (or whatever languages the egg was incubated around). There's a process somewhat like impressment, but the dragon gets at least some choice. And dragon's who loose their captain can live on, and sometimes work with another captain.

The aerial corps doesn't have the prestige of the Navy. They mostly have their bases away from population concentrations (people are somewhat afraid of the dragons), and because some breeds of dragons will nearly only accept female captains, there's rather more sexual equality than in the rest of society (and this is kept secret).

Laurence is chosen by the dragon that hatches from an egg they captured from the French. He figures he has to transfer to the Aerial Corps, and this will be a terrible social hit. Furthermore, his father, who barely speaks to him as it is, will be incensed. However, by page 77 his bonding with Temeraire has proceeded far enough that he wouldn't give up the dragon for any ship in the Navy (and it's a quite honestly affecting scene).

The title is presumably a play on the way warships were named. Temeraire is regarded as a weapon of the crown, commanded by appointed officers.

There's a terribly sad story about a dragon named Levitas, whose Captain doesn't respect, love, or even care for him properly. It's a mini-tale of emotional abuse, ending with Levitas being terribly moved that his Captain even botheed to come see him at the end (only because Laurence literally dragged him out of breakfast). It establishes something about how strong the bonding is at least sometimes on the dragon side. It's like an abused kitten story—willingness to love and trust being exploited and not returned; except that the victim is a multi-ton dragon (he's a small one, but still large enough to haul several people around in the air).

I noticed a number of cases where the people were petting the dragons. In the English service the dragons are considered animals, mostly (though the commander of the training base is a dragon), so it make some sense that people would soothe dragons rather than vice versa (works that way with horses, quite a bit larger than people, too). But the dragons are a lot smarter than horses, and even the fairly dumb ones talk. So it seems strange, and I want to see more of the huge dragons (the bigger ones are 20 tons) comforting their small fragile humans.

So I guess it's an alternate-history fantasy. There's the usual problem that our important people exist, have the same names, and are still important in that world. A difference this big would have changed everything in unexpected ways, and this one has no clear point of departure—dragons have existed forever, they didn't appear recently.

Introducing women as captains because the dragons insist is a useful way to make some social changes at least in the part of society described. But there isn't enough friction between them, I don't think. The aerial corps people are mostly raised apart from age 7 or some such, so it's okay in the corps—but then there should be more trouble when they have to interface with the rest of society. And Captain Harcourt, for example, while she isn't very good at wearing skirts, doesn't seem to resent being forced to do so enough.

As people have commented on rec.arts.sf.written recently, referring to a ship as "a dreadnought" is rather an anachronism. It acquired that meaning with the 1906 ship of that name.

Laurence is a pleasant character to travel around with. When he's being emotionally open with Temeraire, he also has a very distinctive (and pleasant) voice.

And Temeraire, as it turns out, is a Celestial dragon, from China (normally never bonded with anybody but the imperial family). He has a special fighting power, the Divine Wind, otherwise known as roaring load enough to fracture wooden ships. With which he defeats Bonaparte's aerial invason of England.