By Patrick O'Brian

Norton. 262 pp. $24

Reviewed by John Casey

Blue at the Mizzen is the 20th of Patrick O'Brian's novels about the British Navy in the Napoleonic era. The series is both chronological and cumulative; I wouldn't recommend reading it out of order. I hope this is not the last of the line. I have feasted on all 20 of the Aubrey-Maturin novels with the same happy gluttony with which my 9-year-old daughter devours the Harry Potter novels. A reason for hope is that at the end of Blue at the Mizzen Jack Aubrey, having done what he could for Chilean independence, is ordered to take command of the South African squadron of the Royal Navy. Moreover, Jack's dearest friend, Stephen Maturin, the ship's surgeon as well as intelligence agent, is still awaiting an answer to his proposal of marriage. Stephen was married to a splendid but difficult woman, a cousin of Jack's wife, but he is now (1815) a widower.

Among O'Brian's fans there was some disquiet when The Yellow Admiral came out. It seemed more diffuse than the earlier installments. But The Hundred Days (number 19 in the series) was as taut and exciting as the first 17. Blue at the Mizzen is set in year after Waterloo, so it necessarily deals with a period of deflation, both economic and emotional, for the Royal Navy and its ancillary population of shipwrights, chandlers and seamen on the beach. O'Brian covers this state of affairs succinctly and sharply in the first part of the story. Jack and Stephen, however, have the good fortune to be sent to aid Bernardo O'Higgins and Jose San Martin, who are attempting to free Chile from Spain. Of course Jack and Stephen must sail there, and readers are treated to O'Brian's talent for life on board, incidents and accidents -- the apprenticing of a midshipman, a stop in Sierra Leone where Stephen is uplifted by the wildlife but left in mid-air by a woman who appears to be his perfect match. And then into storms, the doldrums, around Cape Horn and into action.

What is the enormous appeal of the Aubrey-Maturin novels? One explanation is that they recapture all those readers who grew up on C.S. Forester's Hornblower books. I was a boy when they came out and I never thought to have those pleasures again, at least not fresh. Although O'Brian is writing about the same wars and the same navy and producing as much action, he is not writing for boys, even grown-up boys. There is a lot more political sophistication. There is a deeper sense of the culture of the age. O'Brian also introduces fairly early on two strong women with quite different attitudes to life, and there are more to come. Stephen's knowledge of and obsession with natural history are a wonderful harmonic to the narrative, as is the description of the medical practices of the early 19th century.

A tactical shrewdness on O'Brian's part is that while Stephen is enormously learned in science, politics, and other fields (he knows Spanish, French, Catalan, Irish and Latin), he is oddly ignorant of ships. Jack is not only a good commander, but he also has a full complement of nautical skills -- navigation (and therefore astronomy and mathematics) and naval architecture. I have it on the authority of a navy veteran and sailing enthusiast that there is one slight technical error in the many pages of sea lore. From time to time the two men fill each other in expertly, briskly and even wittily, and the reader is the third-party beneficiary.

But an even more generally appealing aspect of the Aubrey-Maturin saga is the friendship between the two men. At a meeting of O'Brian readers at a bookstore, I was mildly surprised to see that almost half were women. I asked them what they particularly liked. The answer from 10 or so was that they hadn't thought that men could be such intimate friends, but they found that the Aubrey-Maturin bond made this intimacy plausible, and they were grateful for being able to see -- or at least imagine -- men engaging each other across a full emotional spectrum. Indeed, Jack and Stephen understand each other's anxieties and sadnesses and rejoice in each other's good fortune. In this and in many other ways they are very good men. It is interesting to note that neither is virtuous in a straight-laced way. Maturin uses opium and coca leaves. He also has a fierce temper and fits of prideful contempt. Aubrey has, if not a girl in every port, a number of lady friends from Malta to Gibraltar to the Caribbean (where one of them bears him an illegitimate son). Aubrey is also something of a glutton. Between the two of them they have succumbed to (and resisted) four of the seven deadly sins. Neither suffers from envy, avarice or sloth -- the three cold-blooded sins.

Early on in Blue at the Mizzen, Jack has to ask a favor of Lord Barmouth, the admiral in charge of Gibraltar. Barmouth's new wife is a childhood friend of Jack's, and, before he needed the favor, she and Jack had been renewing their affection wholeheartedly. She bursts into a room where Jack is in the middle of his petition. She is inclined to stay. "Isobel Barmouth was . . . a spirited creature, not to be put down easily nor yet made to leave the room. But she was by no means a fool and it was clear to her that obstinacy at this point might do Jack more harm than anything Barmouth could inflict on her. The admiral was a brave and capable sailor; he had had a remarkable career; and as her guardians had pointed out he was an excellent match. But for all his courage and admitted virtues, she knew he was capable of a shabby thing."

Most of the narrative is from the points of view of the two principal characters, but there are occasional glimpses from other perspectives that both give a capsule story -- in this case a sense of a calculated marriage -- and also provide contrast: Jack, for all his faults, is not "capable of a shabby thing."

O'Brian has written at least one book about the 20th century -- a biography of Picasso -- and he has written Testimonies, a novel set in the 20th century that has some of the flavor of Bruce Chatwin's Under the Black Hill or some of D.H. Lawrence's stories such as "Odor of Crysanthemums" or "The Prussian Officer," all of which have muffled ardor and anguished sexuality as their mood, and the emotional equivalent of cold fog on feverish skin. But at some point O'Brian chose the early 19th century, chose to inhabit it, to gather and spend an encyclopedia of vivifying knowledge so that his characters, particularly the sunlit, energetic Capt. Jack Aubrey and the cooler and more occulted Dr. Stephen Maturin, could sail around a fully realized world. I get the feeling that O'Brian enjoyed himself while producing this series, not just in dove-tailing the fiction into the historical record nor in creating 19th-century speech and thought and the structure of daily life, but in his own daily act of entering a century and world he knows and clearly loves. Perhaps that is the chief reason that one can take in this large and many-volumed story so blithely and satisfyingly: O'Brian did the hard learning long ago and then began to write with fully justified assurance and pleasure.

John Casey's most recent novel is "The Half-Life of Happiness."