THE DANNY Santiago affair was last season's literary sensation. A prodigiously gifted young Chicano burst onto the scene with his stunning first novel, Famous All Over Town -- or so it seemed. But even as critics heaped praise on this new talent, the real Danny Santiago stood up -- a septuagenarian Anglo who had been blacklisted in McCarthy times and who found, for reasons that mystified him as much as anyone else, that he did the best writing of his life in the voice of a man utterly unlike himself in age, background, and experience.

Psychologist Harlan Lane has attempted a similar feat, with equally perplexing results. He could rightly have called his book "Revered Across the Nation," for he takes on the persona of a real individual of great distinction, Laurent Clerc, the 19th-century Frenchman who became a pivotal figure in American deaf education. Better than 95 out of 100 people reading these lines have probably never heard of Clerc or his dramatic work. The other three or four not only know of him but care passionately -- either pro or con -- that he brought French sign language and the French system of signing education to these shores. Perhaps it was to attract a wider audience to this story that Lane chose so unsettling an approach to tell it. Certainly the choice also permitted Lane, already a leading student of deaf history on the strength of The Wild Boy of Aveyron, to express his own deep feeling free from the strictures of his customary scholarly writing. But ultimately it weakens the book -- books, actually -- that Lane set out to write.

The truth is that he seems to have two ideas in mind. In the first place, he wishes to write a complete academic history of deaf education, and to tell the story from the point of view of the deaf. "Hearing students of the deaf have been proceeding on the premise that there is no minority and hence no minority history to tell," he writes. "Until recently, no deaf person had written a history of the deaf community either." What he means is that no deaf person -- or hearing person, for that matter -- had written a scholarly history of the deaf from the point of view of the sign langauge community. Jack Gannon's Deaf Heritage takes a popular approach and covers only the United States; David Wright's Deafness strongly favors the oral methods he grew up with. So Lane determined to write that history.

But he also wanted to write a second book -- one that expresses the emotional reality of the sign language community, its resistance to pure oralism, and the pain that this struggle has cost. To write both these books in one he hit upon the idea of concocting Clerc's "Memoirs," which would tell the story from the Middle es to his death in 1869, with emphasis on the great men and stirring events he witnessed. After Clerc's death, a new voice, Lane's, would pick up the story and carry it to the book's conclusion in 1900.

I SINCERELY wish he had thought the better of this scheme. Because of it, a book that would unquestionably have stood for decades as definitive in its field has been rendered unnecessarily problematic. I do not mean that I find fault with Lane's scholarship. It quite simply takes the breath away. From hundreds of sources, in thousands of footnotes, he lays out everything we might conceivably wish (or even dream) to know about Clerc and his times: what he wore as a schoolboy in Paris, what he ate on the boat to America, where he lodged on fund-raising tours. Some of this detail strikingly illuminates social conditions: the fact that clerc's teacher, the Abb,e Sicard, opposed the move to America on grounds that he would lose his Catholic faith in Protestant Connecticut; the fact that Clerc wed his Eliza almost by stealth because much polite opinion did not approve of deaf people marrying each other. Nor does Lane's industry flag in his descriptions of the scores of other important figures who throng these pages. The English language contains no more complete or meticulously documented account of these events. And since much of this information was formerly available only in French or Italian, Lane has considerably broadened our knowledge.

But why did he have to write this important book in a way that undermines its intellectual integrity? All the while, reading the Clerc portion, one can't help wondering, Is this really Clerc talking or is it Lane? Is this observation or opinion Clerc's or Lane's? If the book succeeded as a piece of imaginative writing, if Clerc came fully alive as a literary character, then perhaps the emotional gain would have justified this risk. Though clear and heartfelt, however, Lane's prose simply lacks the strength to bear this terrific burden. And the ever-prsent footnotes prevent the suspension of disbelief possible and necessary in fine historical fiction. Why not simply write a straightforward biographical history? Biographers and historians commonly write from particular points of view and comment on or interpret the words and actions of their subjects. Calling himself Clerc does not make Lane a deaf man, nor would calling himself Lane lessen the passion or force with which he defends the deaf position.

That very passion, in fact, leads him, in my opinion, to underestimate the vigor and imporance of the sign language revival of the past two decades; but this is a minor point, and essentially outside the period covered in the book. Altogether, I find myself in the unaccustomed critical position of regretting that I must call this a very good book. It could easily have been a great one.