AS A STUDENT at the University of Edinburgh in 1867, Robert Louis Stevenson wore a velvet jacket and his hair long, manifestations correctly regarded as dangerous by his middle-class parents. Yet they doted on him. Nearly everyone who ever met Stevenson doted on him, for he was a bonny talker and a merry rebel against convention, though a mere stick of a man, chronically ill with pulmonary bronchitis, who coughed blood and never at any time weighed more than 115 pounds.

For an invalid, Stevenson lived an uncommonly full and adventurous life. He sailed off northern Scotland, crossed the Atlantic in a cattle boat, wandered alone through the Pyrenees and wintered at various times in the Alps, the Adirondacks, the Napa Valley of California, the Riviera and the artists' colony of Barbizon on the edge of the forest of Fontainebleau. At the end, after roaming the South Pacific, he was the squire of a 400-acre paradise on the slopes of a mountain on Upolu, one of the Samoan Islands -- Vailima, a place of lush trees, flashing waterfalls, deep ravines and commanding views of island and sea.

It is with simple truth, then, that Jenni Calder writes in Robert Louis Stevenson: A Life Study , "One of the irresistible features of Stevenson's life is that it makes such a good story." Her book is pretty irresistible itself, an affecting story of human endurance and love and a writer's struggle for expression. Calder could easily have written a volume many times longer -- the catalogue alone of the Stevenson collection at Yale's Beinecke Rare Book Library fills six volumes. Her biographis is a model of economy, with every word pondered and exactly laced, not surprising considering her impressive credentials. Calder is the daughter of critic David Daiches, who wrote an acclaimed study of Stevenson, and a native herself of Edinburg, Stevenson's beloved city of "belching winter winds," intimate as no outsider could be with that ancient capital. One assumes that Calder first got her Stevenson, like all good Scottish children, along with her porridge.

Clearly Stevenson received Scottish history, and Walter Scott and Robert Burns, along with his porridge. He was born in Edinburgh on November 13, 1850, the only child of Thomas and Margaret Stevenson. His mother was the daughter of a Presbyterian minister; his father was a harbor and lighthouse architect with the romantic title of Commissioner of the Northern Lights. Each parent came from a family of 13 children; a physician uncle fought cholera in India. "Louis always hoped to find Highland ancestry for the Stevensons; an unnecessary flourish," notes Calder. Unnecessary because Stevenson's famiy "represented solid Scottish achievement at its best. Religion, technology, mdicine; if at the end of the eighteenth-century Edinburgh was seen as a cultural and philosophical centre of Europe, by the middle of the nineteenth it was these things that made its reputation, and these along with soldiers that Scotland exported so liberally to every corner of the Empire."

An important influence was his nurse, Cummy, a diminutive for Alison Cunningham, "a product of strict Calvinism, born and bred across the water in Fife." She fed him the literature of the Covenanters, the Presbyterian opponents of episcopacy in the 17th century, "vivid and bloody stories of religious dedication and martyrdom."

The family lived in Edinburgh's New Town, whose fine 18th-century houses looked across the valley to the decaying Old Town, abandoned by the upper classes, where lingered memories of grave-robbers and murderers, "of Jacobites and Covenanters and Border raids, of rebellion and fanaticism, of a savage past from which he was never to escape." Above both towns loomed the old castle, from whose ramparts were prospects of the hills that ringed the city: the Pentlands, the Lammermuirs and the Ochils across the Fifth of Forth.

Stevenson wanted to write, but like James Boswell a century before, paternal insistence requird he first learn a profession. He entered the university and graduated in engineering; to please his father even further, he studied law, actually being admitted to the bar (Stevenson's literary parodies of lawyers' mumbo jumbo were always to very sharp). The flaunted bohemianism no doubt made this regime somewhat bearable, but psychologically and physically at a low point, he soon began the restless wanderings in search of a healthy climate. On an extended vacation to Barbizon in France in 1879 occurred the coup de foudre that changed his life. He met and fell in love with Fanny Osbourne. She was 10 years older than Stevenson, an American, married and the mother of two children. Her husband, Sam, was a wastrel. After a year's separation, a virtually penniless Stevenson followed her to San Francisco. She divorced Sam Osbourne, and they were married. They honeymooned in the Napa Valley in a bare hut they called Silverado.

"Trusty, dusky, vivid, true" Fanny provided Stevenson with a stable emotional atmosphere in which to write. Once settled down -- that is, as far as it can be said that Stevenson ever settled down -- he was astonishingly productive: One after another came Treasure Island (1883), A Child's Garden of Verses (1885), The Strange Case of Dr. Jekyll and Mr. Hyde (1886), Kidnapped (1886), The Black Arrow (1888) and The Master of Ballantrae (1889), merely to name the more famous works. There were also short stories -- some very good ones, like "Thrawn Janet" and "The Beach of Alesa" -- travel books, poems, plays and numerous starts that were put aside.

Was Stevenson a great writer? Contemporaries, like Leslie Stephen and Henry James, thought he had the makings of greatness. He certainly was a superb writer. If this be doubted, reread Kidnapped (preferably in the edition magicaly illustrated by N. C. Wyeth). The prose is beautifully controlled, the action never forced. The reader is swiftly captured by the adventures of David Balfour in the Highlands in the wake of the Jacobite rebellion of 1745. The story has everything: wicked uncle, shipwreck, desert island, assassination, ambush, clan feuds (Campbell vs Stewart of Appin), a flight by moonlight across the moors and a lost inheritance. In the conclusion the hero succeeds to his estate, becomes a laird, David Balfour of Shaws, and is last seen -- where else for a Lowland Scot? -- entering an Edinburgh bank.

This is escape literature, not just a classic yarn for children. It is wonderful stuff, the forerunner of Rudyard Kipling, John Buchan and C.S. Forester. Calder doesn't venture an opinion of Stevenson's literary impact, but here is what her compatriot, J. I. M. Stewart, has to say about Stevenson's literary escapism in his volume of The Oxford History of English Literature : "He hands on to innumerable popular writers a tradition in which it is important that a gentlemen should know just when to draw. his sword or punch a gangster on the jaw. If gentlemen are no longer put to making these calculations -- except, indeed, in conditions of mass slaughter -- it is perhaps the gentlemen who are doing the escaping as well."

Many admirers have thought Stevenson was moving a mature phase when he died, perhaps burstling the straitjacket of the prevailing sexual prudery -- after all, he wrote in an era when his editors, to Stevenson's fury, deleted a reference to a bogus marriage certificate. Much of the admirers' claim for a new phase is based on the unfinished Weir of Hermiston , a complicated novel of seduction and revenge, published posthumously in 1896. Calder rightly rejects the claim: "Weir of Hermiston is perhaps a red herring, best left out of the final assessment, certainly if it is only used to indicate what Stevenson might have done . . . Louis was compulsively a Scottish novelist yet, if we are looking for clues as to what he might have become most memorably a novelist of the contemporary Pacific scene, an explorer of alienation and isolation, an analyst of values, akin to Joseph Conrad."

One can always speculate, however. I like to think that Stevenson's attachment to Scottish subjects, heightened by his sense of exile and the loosening of fusty moral codes, might have led him into writing a rollicking novel of his youth, set in the peroid of his university days when he went drinking and whoring through the demimonde of Edinburgh, catching a mighty bad case of Calvinist guilt. (Such a bad case in fact, says Calder, as to help explain the origin of Jekyll and Hyde and the fascination with evil in all his books; Long John Silver, not the boy Jim Hawkins, is the real hero of Treasure Island .) What a novel these youthful indiscretions might have made, evoking Victorian Edinburgh the way James Joyce's portrait of the Artist as a Young Man evokes Edwardian Dublin.

The demands of his extended family, hangers-on and retinue of retainers at Vailima broke Stevenson's health. On December 3, 1894, while standing on the verandah talking to Fanny, he collapsed from a cerebral hemorrhage, dying that night. He was 45, at the height of an immense popularity, already a legend, a South Seas romancer before Conrad, an exile before Joyce. His Polynesian servants in tartan lavalava skirts buried their laird in a Union Jack-draped coffin on a mountaintop, a place caressed by the trade winds, a corner of a foreign field that is forever Scotland. The famous epitaph on the grave contains the only lines of Stevenson's poetry that many people know: Here he lies where he long'd to be; Home is the sailor, home from sea, And the hunter home from the hill .

But the epitaph Calder prefers is another Stevenson poem, at once more intimate and more Scottish: Blows the wind today, and the sun and the wind are flying, Blows the wind on the moor today and now, Where about the graves of the martyrs the whaups are crying, My heart remembers how! Grey recumbent tombs of the dead in desert places, Standing-stones on the vacant wine-red moor, Hills of sheep, and the howes of the silent vanished races, And winds, austere and pure: Be it granted to me to behold you again in dying, Hills of home! and to hear again the call; Hear about graves of the martyrs the peewees crying, And hear no more at all .

"I would like to think," Calder concludes this excellent book, "that in the last dazzle of reality he saw the bleak tombstone of a Covenanting martyr, saw a curlew rising above the Pentland Hills."