He is best remembered as the creator of Sherlock Holmes, although he thought his historical novels ("The White Company," "Sir Nigel," etc.) represented his finest work. But would you believe Sir Arthur Conan

Doyle's favorite among all his characters was the hero of his science-fiction stories, the irascible George Edward Challenger?Doyle a science-fiction writer? Yes indeed, albeit in something of a Jules Verne-Rider Haggard vein. Thus Professor Challenger first bullied his way into print as the discoverer of "The Lost World," published in 1912. Penetrating the then-largely-unexplored Amazon basin, he and his colleagues come across a high plateau teeming with prehistoric life, including ape-men and dinosaurs, finally bringing one of the latter - a pterodactyl - home to England.

This was followed a year later by "The Poison Belt," a novella in which the black-bearded professor and his friends observe, from a uniquely British vantage point, what they believe to be the end of the world, as the Earth moves into a belt of deadly gas. Then, toward the end of Doyle's life, came three more Challenger stories: "The Land of Mist" (1926), "When the World Screamed" (1928) and finally, in 1929, "The Disintegration Machine."

Chronicle Books (which a year ago gave us a magnificent volume on the Steinway piano) has now gathered these into two volumes, a convenient and, as far as I am aware, unprecedented compilation.

Of the five stories the first, "The Lost World," is still the best. Not only is Challenger in his element, enthusiastically throwing reporters down the steps and taking on the scientific establishment, but the descriptions of the dinosaur land border on the gothic, calling up the engravings of Gustav Dore as surely as the Holmes stories evoke the gaslit world of late-Victorian London.

"It was dreadful in the forest," Doyle's narrator, the Watsonlike Edward D. Malone, informs us. "The trees grew so thickly and their foliage spread so widely that I could see nothing of the moonlight save that here and there the high branches made a tangled filigree against the starry sky. . . . I passed close to the pterodactyl swamp, and as I did so, with a dry, crisp, leathery rattle of wings, one of those great creatures - it was twenty feet at least from tip to tip - rose up from somewhere near me and soared into the air. As it passed across the face of the moon the light shone clearly through the membranous wings, and it looked like a flying skeleton against the white, tropical radiance."

Very little in "The Poison Belt" is on that level, especially the denouement, in which the supposed death of all mankind proves to be only a temporary snooze. Reminding us that, for all Holmes' clearsightedness and clinical perspicacity, Doyle's science fiction lacks both the mystical depths of Haggard and the scientific grounding of Verne, with whom one can almost imagine these things coming to pass. As in fact many of them have.

That seldom if ever happens with Doyle. Rather his saving grace is his humor. When Challenger and his cronies happen upon another survivor of "The Poison Belt," an elderly invalid whose oxygen has spared her, her first question on being informed of the calamity that has befallen the rest of the world is, "What effect will these events have upon London and North-Western Railway shares?"

Remarkably, that same quality surfaces most winningly in the last two stories, "When the World Screamed," in which Challenger, by boring beneath its crust, makes even the Earth take notice of him, and "The Disintegration Machine," whose diabolical creator is dispatched in almost "Twilight Zone" fashion. Remarkably because they would seem to give the lie to the falling-off apparent in both the later Holmes stories and, most dishearteningly, "The Land of Mist," which despite its Haggardlike title emerges as pretty much a spiritualist tract.

Here the skeptical Challenger is finally converted to Doyle's own spiritualistic point of view, one that obsessed him the final decades of his life. The problem, however, is not whether or not we share his outlook but that almost nowhere are we really caught up in the narrative. After all, one does not need to believe in reincarnation to be gripped by much of Haggard, or go along with Doyle's largely negative opinion of the Mormons to enjoy "A Study in Scarlet." Leading one to concur with Hesketh Pearson, who, in discussing Doyle's selection of Challenger to advance the cause, says, "We can only feel profoundly thankful that their creator was fonder of Challenger than of Holmes."

But then maybe you will be, too.