The first of over twenty Napoleonic War adventures by Patrick O'Brian, replete with period and naval detail - this series is well enough known by now that it needs no introduction and indeed this, although it is the first book, isn't recommended as the first to read as it does sometimes get bogged down in minutiae and description.
Considering most of the action is between the eastern coast of Spain and the Balearic Islands aboard Jack Aubrey's first command as captain, the HMS 'Sophie', O'Brien does get a lot of mileage out of it and at times although you have to imagine the scene in the minds eye it bears doing as you can get for example the feel of being on a small and outdated warship suddenly confronted by three enormous enemy ships of the line. He matter of factly describes floggings and the decks running with blood after a battle - there is no attempt to put an anachronistic modern worldview except perhaps the level of national identity going on with the Catalan/Irish Stephen Maturin - there was not much Catalan identity at this point in history, it surfaced again in the mid 19th century having been insignificant since the late Middle Ages.
Aubrey and Maturin are a nicely matched pair - both cultured fighting men, although in Aubrey's case it's the culturedness that is surprising and in Maturin it's the other way round.