The opening 15 minutes of ''Master and Commander: The Far Side of the World'' are so well crafted that they restore your faith in commercial cinema. Hollywood has become sloppy at the basics of time, place, and mood, but director Peter Weir (''Witness,'' ''The Truman Show'') gives us a refresher course in what it's all about: A massive fighting ship plows silently through a misty dawn at sea, crossing our field of view like the spaceship at the start of ''Star Wars.'' Brief titles tell us what we need to know -- April 1805, Napoleon is grabbing for all of Europe, ''oceans now are battlefields'' -- and then Weir plunges us belowdecks to glance at the sleeping crew hung like crowded bags of suet in their hammocks, the silent cannons, livestock restlessly moving about. Back in the open air, the dogwatch peers through the fog, having glimpsed something. Maybe. The captain is awakened. A flash of orange blooms in the murk and the morning turns into a slaughterhouse.
We have no idea just yet who is fighting, or why, but as we watch the spars of the HMS Surprise splinter in the cannonade, as men are dismembered without warning, and as Captain Jack Aubrey (Russell Crowe) tries to patch his crippled vessel and escape, we know we're watching real moviemaking. ''Master and Commander'' eases its sails somewhat after that opening salvo, but it doesn't slack off until the very end, after the action has come full circle and we're left with the sight of two contrary yet inseparable men wondering where to go next.
In the celebrated 20-volume series of novels by the late Patrick O'Brian, there was always another historical adventure for ''Lucky Jack'' Aubrey and
Stephen Maturin (Paul Bettany), his ship's surgeon, musical partner, friend, and gadfly, to embark upon. The plot of ''Master and Commander'' has been cobbled together from the first and 10th books of the series, as its awkward portmanteau of a title suggests, but against all hopes the finished film is of a piece. Weir departs enough from naval history and from the books to give the diehards fits, but as a junior-lieutenant-level O'Brianite (having read the entire series only once), I'm here to tell you the movie works -- as an epic, as intimate drama, and as an intensely focused portrayal of a small wooden city on the sea. Better yet, you don't have to be able to tell a hawser from a halyard to enjoy it. All you need to know is that the Surprise is in Pacific waters chasing the Acheron, a much larger French privateer sent to harass and plunder the whaling fleet of England. After that initial skirmish, Aubrey limps off to refit his ship and tail the Acheron east around Cape Horn in a storm -- filmed by Weir as an impersonal apocalypse -- finally using guile and luck to close with his adversary.
As it was for O'Brian, the real subject of ''Master and Commander'' is how men in isolation fashion themselves into a community. Weir understands that this is the story of civilization itself, and on board the Surprise it plays out on every stratum of the crew, from the doughy-faced able-bodied seamen through the midshipmen and all the way to the captain's quarters. We see the crew turn against a fumbling junior officer (Lee Ingleby), convinced he's a ''Jonah'' who brings bad luck. We also see their superstition war with awe at the wonders of modern medicine when Stephen operates on a seaman's brain on the open deck.
Stephen is our surrogate, of course -- a humanist intellectual who splutters with disbelief at the more medieval aspects of the Royal Navy (Jack, by contrast, understands the value of the occasional flogging). The doctor is also a naturalist who falls upon the tortoises and boobies of the Galapagos Islands with Darwinian joy, and he's a skilled enough surgeon to, in one brutal scene, operate on himself. (What he's not, unfortunately, is a spy; the espionage activities that make some of the best chapters in O'Brian's novels are nowhere to be found in the movie. This is a little like neglecting to mention that Clark Kent is also Superman.)
Bettany and Crowe played roommates, one of them imaginary, in ''A Beautiful Mind,'' but here they make a very different sort of team. Surprisingly, Crowe buries his charisma and gives us an intuitive jock who thinks not with his brain but with his men and his ship. He has put on pounds -- in the books, Jack constantly struggles with his weight -- and he uses that bulk to suggest an authority that can be easygoing or unyielding as the occasion demands. It's the opposite of the sexy beast of ''Gladiator,'' yet you immediately grasp why Jack's men follow him nearly to Antartica and back.
Bettany has the harder task of playing a lubberly bookworm without coming off as a twit, but he understands that the more prickly Stephen is, the more we like him. The other roles are pungent but smaller; O'Brian readers will recognize Jack's grumbling steward, Killick (David Threlfall), and capable second-in-command, Tom Pullings (James D'Arcy); ''Lord of the Rings'' fanatics will be happy to see Billy Boyd, a.k.a. Pippin, as coxswain Barrett Bonden; and other moviegoers may just get lost among the muttonchops.
Which brings up an interesting question: Who's the audience for this film? Is there an audience for this film? ''Master and Commander'' doesn't play fast and loose with the genre, like this summer's ''Pirates of the Caribbean,'' and Crowe certainly doesn't mince around like Johnny Depp. Weir has quite consciously made an old-fashioned work that predates the Age of Irony, and it will be interesting to see if it floats with audiences who prefer to be reminded of their own hipness.
The film does lose steam after its climactic battle -- the dialogue turns self-conscious, and Crowe and Bettany suddenly seem somehow smaller, like an early-19th-century Kirk and Spock. This is not a good thing. Patrick O'Brian wrote characters who flourish in action, not reaction, and it may be that he kept churning out sequels in an effort to keep his two heroes alive. The movie, too, ends with Jack and Stephen looking uneasily past the end credits toward the next adventure.
In the words of another captain: Make it so.