DEVOTEES OF PATRICK O'BRIAN'S celebrated series of historical novels are likely to be not just relieved but delighted by Peter Weir's beautiful film "Master and Commander: The Far Side of the World."

They had reason to be worried at the prospect of a Hollywood version of the beloved Aubrey-Maturin novels. The twenty-volume series, set during the Napoleonic wars, mostly aboard British naval vessels on the high seas, is too literary and language driven, its humor too subtle and dry, to be promising movie material (although you can just about imagine a "Masterpiece Theater"-style miniseries). Worse, the stories form a fairly tight chronological sequence, and the title of Weir's film combines the titles of O'Brian's first and tenth books in a worrisome way.

All of which means that Weir's "Master and Commander" is a small miracle: a genuine achievement in literary adaptation. For all its beauty and excitement, there isn't a movie-ish moment in the movie. Every scene demonstrates a restraint and intelligence that accord with the spirit of O'Brian's work.

Perhaps the most important thing to point out to non-initiates is the Aubrey-Maturin books are not precisely "genre fiction," the pejorative term of literary snobbery used to damn even the best detective, science-fiction, western, and romance novels. They are not maritime adventures (in England there are whole sections of bookshops devoted to the genre) like the Hornblower stories of C.S. Forester (although these are underrated and inspired a very good British television series), Dudley Pope, and Alexander Kent. Rather, as Richard Snow wrote in

The maritime setting is extremely important, and the books are full of authentic technical detail comprehensible only to the most educated sailor (O'Brian was steeped in eighteenth-century maritime lore and literature). But they are also works of brilliant imagination. (O'Brian's imagination was so rich, it flowed into his accounts of his own life.) The books are really about the unlikely friendship of two men: a bluff English sea captain named Jack Aubrey, and Dr. Stephen Maturin, a half-Irish, half-Catalan ship's surgeon who is also a brilliant naturalist, a laudanum addict, and a secret agent for the British admiralty. Three things unite this pair: a love of music, a devotion to the war against Bonaparte, and a mutual admiration. The books are considerably less accessible and more learned than most historical fiction. But soon after Norton reissued the series in 1990--to be championed by such writers as Snow, Mark Horowitz, and John Bayley--they began to win a remarkably large audience.

O'Brian writes in an invented language that sounds like eighteenth-century English--although, as you can tell if you compare it with the language of Smollet and Fielding, it's really a brilliant pastiche composed of slightly archaic vocabulary and syntax interspersed with genuine expressions of the era. One of O'Brian's signature techniques is his eccentric, elastic sense of time, accelerating and slowing down in sometimes unpredictable ways. A teasing charm of the books is the way O'Brian takes the reader in great detail to the beginning of a battle--and then cuts to its aftermath, so that you discover how it all worked out in casual remarks at a gunroom dinner.