<i> Mademoiselle:</i> : Conversations with Nadia Boulanger : by Bruno Monsaingeon, translated from the French by Robyn Marsack (Carcanet: $14.95; 160 pp., illustrated)

Nadia Boulanger thought of herself simply as a teacher. That’s a little bit like thinking of Michelangelo as an illustrator, Beethoven as a tunesmith or Shakespeare as a storyteller.

Boulanger was a force, a landmark, a gauge. Her one-woman school in Paris, affectionately known as the “Boulangerie,” shaped destinies. She made a decisive impact on several generations of important 20th-Century composers, many of them Americans: Aaron Copland, Virgil Thomson, Walter Piston, Roy Harris, David Diamond and Elliott Carter, not to mention Philip Glass and Quincy Porter.

The public at large may not have known her all that well, though she did make distinguished contributions as a conductor and organist both in concert halls and recording studios. Serious musicians knew her, however. They also feared her, revered her, jostled for her approval.

According to Nicolas Slonimsky, that most dauntless and exhausting of lexicographers, Boulanger did not instantly enchant all her charges. Some reportedly complained about “the strict, and even restrictive, discipline she imposed . . . but all admired her insistence on perfection of form and accuracy of technique.”

In her teaching, she stressed counterpoint exercises and analysis of music of all periods. According to the scholar, Dominique Jameux, “she impressed her students by her close acquaintance with an immense body of music, her quickness to note the failings and successes of a composition (provided it accorded to some extent with her taste) and her regard for the sacred vocation of the artist.”

Born in 1887 to a French father and a Russian mother, Boulanger studied organ and composition at the Paris Conservatoire. Her own teachers included Vierne, Widor and Faure. In 1908, she won the second Prix de Rome for a cantata entitled “La Sirene.” She forswore composition at an early age, however, probably because she felt her work could not compare with that of her adored younger sister, Lili.

Her tastes were, to put it mildly, eclectic. She was an admirer of Debussy, a disciple of Ravel. Although she bore little sympathy for Schoenberg and the Viennese dodecaphonicians, she was an ardent champion of Stravinsky (she led the premiere of his “Dumbarton Oaks” in Washington in 1938). She served as a pioneer in the revival of French music of the Baroque and Renaissance and, between world wars, played a crucial role in the rediscovery of Monteverdi.

In 1937, accepting an invitation from the Royal Philharmonic, she became the first woman to conduct a symphony orchestra in London. A year later, she became the first woman to conduct a subscription concert by the Boston Symphony. A comparable milestone with the New York Philharmonic followed in 1939.

During the war, she taught at Radcliffe, Wellesley and Juilliard. Returning to Paris in 1946, she remained a veritable mecca--an institution, despite declining health. Her 90th birthday in 1977 elicited international tributes. Fontainebleau celebrated with the release of huge hot-air balloons. She died two years later.

The American publishers of “Mademoiselle” have heralded Bruno Monsaingeon’s slender volume as “the definitive biography of this century’s greatest music teacher.” Boulanger may indeed have been this century’s greatest music teacher, but the new book about her (new here, though already 4 years old in France) isn’t a biography at all. Anyone in quest of a historical portrait must turn to Leonie Rosenstiel’s “Nadia Boulanger: A Life Devoted to Music” (New York, 1982) or, perhaps, to Alan Kendall’s “The Tender Tyrant” (London, 1977).

Monsaingeon--a Paris-based violinist, film maker and musicologist--has simply recorded, collated, organized and refocused some “conversations” registered during the last six years of Boulanger’s life. The sources are interview transcripts, excerpts from her writings and recalled dialogues. The primary material is complemented with memorial tributes from nine illustrious students and colleagues (the most mawkish by Leonard Bernstein), a skimpy biographical chronology and a surprisingly brief discography.

Boulanger emerges in these verite documents as an essentially unsentimental, occasionally nostalgic, supremely courteous savant. Sounding prim, proud, sometimes spry and sometimes weary, she discusses her family, her pupils and her collaborators. Within prescribed limitations, she offers a view of her profession and, grudgingly, of herself.

“I don’t like talking about myself,” she declares in an early chapter that Monsaingeon whimsically entitles, “Overture a la Francaise.”

“Who would find it interesting? I don’t even know to whom I should leave things. . . . To most people . . . I am already more in the land of the dead than of the living; so we can’t talk about me all day long because it is of no interest to anyone, especially not to me!”

Later, she recalls a visit with Faure, her old teacher. The composer chides her for having given up composition. “ ‘Oh,’ I replied, ‘ Cher Maitre, if there’s one thing I’m sure of, it is . . . that I wrote useless music. I am tough enough with others, so I should be tough with myself.’ ”

Nevertheless, Boulanger admits that she was touched when Faure went to the piano and, from memory, played a variation she had written for him at age 15. She tells Monsaingeon that she had often regarded Faure as a dreamer. On the day she turned in the exercise in question, she had thought that “he’s not really listening.”

In another chapter, Monsaingeon asks Boulanger if she can impart both technique and elan to a student. “Ah, now,” she replies. “ He has to have the elan. “

She reminisces about her work with a Bulgarian prodigy: “From the beginning, I said to him: ‘Never do what I might say to you in a weak moment if it seems to you I’m mistaken.’ ”

She remembers, with obvious approval, what Manuel de Falla told her after a concert by the young Menuhin: “Yes, yes, it overwhelms me, a child prodigy. But what shatters me even more is an elderly prodigy. Verdi writing ‘Falstaff’ at 80 astounds me more than Mozart writing his masterpieces at 20.”

Small irritations occasionally punctuate the illuminations. Monsaingeon permits some awkward breaks in continuity. As an interviewer, he is often too awed by his subject, or perhaps by her age and infirmity, to challenge a point, to probe or to argue or demand further elucidation. After a few chapters, a certain aura of piety threatens.

Some details in the appended sections do not bear close scrutiny. Boulanger certainly never was the “chief conductor” of the Boston Symphony. The New York Philharmonic should not be confused with the New York Symphony Orchestra. Perhaps such passing blemishes can be excused as the byproducts of a problem-ridden translation.

In the final analysis, the irritations seem trivial. “Mademoiselle” stands as a poignant testament to an extraordinary, and extraordinarily influential, mind.