IT IS THE fantasy of every Sherlockian that Sherlock Holmes, with Dr. John H. Watson, did in fact pursue justice among the befogged and criminalled London streets of the late 19th century, and that Dr. A. Conan Doyle was merely the alter ego Watson annexed so as to fictionalize his accounts. Fantasy perhaps, but with the publication of The Seven-Per-Cent Solution, we have at last some substantiation that Watson, at least, actually lived--and died in 1940--and that Doyle was only the distracted doctor and inoffensive scribbler we'd like him to be. We owe these revelations to Nicholas Meyer (evidently a hack on the rise, he wrote 400 film reviews for his college paper) who had the good fortune to be in the right place when Watson's last manuscript surfaced in a London attic 31 years after it left Dr. Watson's control.

Whether Holmes ever lived outside Watson's cranium is doubtful, especially as this bizarre tale of The Seven-Per-Cent Solution overtaxes the reader's suspension of disbelief. Apparently Watson lay in the fell grasp of senility when he delivered this blithering monologue to a secretary in an old-age home, and Nicholas Meyer distilled it all.

The story is masterful. It is 1891 and Holmes's fondness for cocaine is now an addiction. He has acquired a phantom: Professor Moriarty, a shuffling grammar-school teacher who becomes "the Napoleon of crime" when the sleuth is in a narcotic state. Shocked but dutiful, Watson lures Holmes to Vienna where the possessed detective encounters the equal genius of Sigmund Freud.

Freud cures Holmes and it is not long before they discover an adventure to involve both their powers. A wronged and beautiful American innocent leads them quickly to a scarred and diabolic German. Holmes realizes that the fate of Europe hangs in the balance, as the evil man is scheming to take over the largest munitions factory on the continent. Holmes and Freud are reduced to primitive stokers during a dynamic train chase to the Bavarian border where the story climaxes.

WHOEVER OUR AUTHOR is--the aging Watson or the youthful Meyer--he has created this tale out of the stuff of the traditional Holmes canon in a brilliant and startling fashion. The Reichenbach Falls death-struggle of the Final Problem has been elevated here to a hellish showdown above a train careening through the Bavarian mountainscape. The Moriarty mystique has been defused until it becomes simply Holmes's refracted trauma at having discovered two skeletons in his father's closet. And the story, with its pivotal heroine, its deferentially anonymous references to European nobility, its global crisis in the offing, and even its fixation on the "points" of a railroad track, emerges as a hybrid of "A Scandal in Bohemia" and "The Adventure of the Bruce Partington Plans" and "The Adventure of the Second Stain."

Unfortunately, that is not all the author dragged out of the originals. Our narrator is a pedant, and he felt obliged to introduce within his meager 250 pages a galaxy of references to earlier adventures, to all of Holmes traits and methods, and to some of the fascinating characters and animals that our author evidently feels were snubbed because they were mentioned only once in the original.

When the chronicler decides to develop these allusions to the canon into important plot devices, they are terrific. In the original, neither Holmes's cocaine consumption nor the intelligence of Mycroft Holmes was a significant subject, although both matters have since tantalized all inquisitive Sherlockians. In The Seven-Per-Cent Solution, they have flowered into captivating themes.

The narrator does not display the same literary tact in regard to other aspects of the Holmes figure. The detective's penchants for frenetic violin playing, for contemplative shag-smoking, and for energetic telegraphing are all thrust into the story because they were effective in the original. The sacred Holmes sleuthing ritual--the animal-like absorption in the tracing of a clue--has been neatly reduced to a series of yelps, whines, and tremors that has been blandly placed into the narrative.

A most remarkable scene in The Seven-Per-Cent Solution reunites Holmes with the fine nose of the hound Toby, but the scent they are following is not the foul musk of creosote, that criminal excrescence from The Sign of the Four, but the rather innocuous odor of a man who is steeped to the ankles in vanilla extract. This may be a fine touch for the Sherlockian satirist--and there have been plenty of them--but it hardly befits the genius of Watson. Because of preposterous insertions, like this pun: "You've a real gift for telling a tale, Watson, and a flair for titles, too, I'll be bound," or the following canard: "On that previous occasion Holmes wished to employ Toby in order to trace an orangutan through the sewers of Marseille," one comes to rue moribund Watson's addled state or to suspect the young Meyer of a deceitful forgery.

The vocabulary of The Seven-Per-Cent Solution is true enough--there are plenty of invernesses, ulsters, and muftis; hansoms, fiacres, and landaus. But the action is too quickly transplanted to Vienna, and so misses the iniquitous intricacy of the London street map. London, beshrouded and inscrutable, is the sprawling metropolis where multitudes of little souls fumble for what they have lost: their lovers, their jewels, their geese, their clerkships, their sense of proportion--and Holmes is the rare mind who can find his way about. No wonder our author feels out of place in Vienna and slowly molds it back into the London of the canon. He homes in on squalid quarters and warehouses by the river and at last even transforms Freud's apartment at Bergasse 19 from a sedate and bookish settlement into the familiar malodorous and cluttered Holmes thinktank.

BUT IF THE book depends on its originals, it also detaches itself from the concerns of the detective novel. The narrator appears to mock the readers or himself, to perform little changes in the Sherlockian from that betray his aloofness. For instance, in spite of his skillful story, the author endeavors to give the piot a fine little flaw (involving the two women of the adventure). In addition, some of his sentences are disjointed in a profoundly jarring way, as if they have been lifted straight from the canon and scrambled slightly to fit the story here.

Perhaps the author gives himself away when he discusses the "points" of the railroad track at the end of the book. Watson must regularly jump off the train to switch these points so that it will follow the route of the sinister Baron's locomotive. Over and over again our chronicler writes, the points must be switched: "And the points--the points are all wrong!" One can't help but sense that he is pointing fun at the defects of the traditional detective novel.

So, dammit, I guess Watson didn't exist or at least didn't write this adventure. No, this book must have been written by Nicholas Meyer after all and although it is a dastardly counterfeit--with lots of spurious biographical information on Dr. John Hamish Watson--Meyer has the good sense to give himself away in the end.