Classical composer Wolfgang Amadeus Mozart has become a cultural icon whose image and music are used to sell everything from cars to chocolates. Can there be anything new to say about him or his music?

Neal Zaslaw thinks so, and classical music scholars worldwide will be able to debate whether he is right or wrong in a few years, when his current research project, a new edition of the Koechel catalogue that lists Mozart's works, is published. He expects it to be controversial.

Zaslaw, the Herbert Gussman Professor of Music at Cornell University, is the first American to edit the standard Mozart chronology, compiled by Ludwig Ritter von Koechel and first published in 1862. Zaslaw's edition, the fifth or the ninth, depending on how one counts, will be the first to be published in both German and English.

His selection for the editorship by the German publisher Breitkopf & HaErtel in 1993 reflects Zaslaw's standing as one of the world's most respected musicologists, a reputation he has earned over the past 30 years through his research and publishing, his involvement in seminal recordings of works played on original instruments and -- most recently and notoriously -- his role as musicological adviser for Lincoln Center's 1991 Mozart celebration, an undertaking so vast that The New York Times dubbed Zaslaw "Mr. Mozart."

Recognition has also come from the American Academy of Arts and Sciences, which in May named Zaslaw a fellow, an honor that he said "pleased me immensely, because it means people outside your own field have taken an interest in your work."

Zaslaw describes his seven-year editing project on the Koechel catalog as being immersed in "a lot of picky details" and "the side of musicology that makes most people yawn." But he quickly adds that the results of the scholarly slogging are anything but boring. Koechel's original catalog documented 626 works by Mozart and numbered them in chronological order according to when they were composed. Koechel's successor editors added newly found works to the catalog, inserting them to fit the chronology and renumbering many of the others.

His new edition of the Koechel is bound to be controversial, Zaslaw predicts, because he is observing stricter rules for evidence of authenticity than previous editors used, and he will be tossing out some works that have been widely accepted as Mozart's.

"Of the 626 works in Koechel's original catalog, probably 60, 70 or more are not by Mozart," Zaslaw says. "When I was growing up, and in the current edition, for instance, there are four flute quartets and two flute concertos. I think, when we are finished, we will have thrown out two concertos and two quartets, or at least placed them in the questionable category."

Zaslaw intends to return to Koechel's original enumeration, which includes only complete works in the main catalog, and separate listings for sketches, fragments and lost works, with an appendix for works that cannot be authenticated.

Authenticating each work is, literally, a global process, because Mozart's original manuscripts are in public and private collections all over the world, sometimes even dismembered and scattered.

"The very famous works are not in question," Zaslaw says, "because we have the original autographs for most of those, but some earlier works are in trouble. Anywhere I travel, I try to look at the manuscripts, but I will never be able to look at them all -- the catalog would never get done. Where there is a problem, or if there is disagreement about contents, I look at the manuscript or ask someone else to look at it and see what the problem is."

Two associate editors, Ulrich Konrad of the University of Wuerzberg and Cliff Eisen, a Cornell Ph.D. who teaches at King's College in London, are assisting Zaslaw, as are members of a board of German, Austrian, American and British advisers.

Until now, Zaslaw has been teaching both undergraduate and graduate courses while working on the Koechel catalog, but he is going to be a full-time editor starting this summer. He will be on sabbatical for the fall semester to complete his manuscript, which will go to his associate editors for review and then to the publisher for translation into German. He will return to teaching in January, while waiting for the expected publication of the new Koechel early in the next millennium. It will be a major event in the world of classical music, and Zaslaw is reluctant to guess how all of his editorial revisions will be received.

"Like any scholar, I dread making mistakes," he says, "but as a sensible person, I know there will be some. Some of my colleagues will like this edition, some will not like it."

Zaslaw is no stranger to controversy in the classical world. The 1991 Lincoln Center festival to commemorate the bicentennial of Mozart's death drew strong reactions from critics. Zaslaw assisted in putting together a 19-month program that presented all of the works attributed to the composer. Some New York critics complained that this was much more Mozart than anybody ever needed to hear.

Ironically, 1991 wasn't the first time Zaslaw was told there was "too much Mozart." As a graduate student in musicology at Columbia University in the 1960s, he wanted to do his thesis on Mozart but was told Mozart was already "done." So he chose another composer for his thesis but kept his fascination with Mozart. Describing his father in an interview as a "Mozart freak," Zaslaw had grown up in New York City listening to the composer's music and performing it on the flute. He did undergraduate work in psychology at Harvard, then went to Juilliard for a master's degree in performance in 1963. He then spent three years as a flutist in the American Symphony Orchestra under Leopold Stokowski before going to Columbia for his doctorate.

Zaslaw came to Cornell in 1970 as an assistant professor. During a sabbatical in London in 1976 and 1977, he met director Christopher Hogwood, who was just beginning to put together performances of orchestral music on original instruments. Their collaboration in recording Mozart's 68 symphonies was one of the most important events in classical music of the decade, helping to launch a whole movement in performance on original instruments that is still very popular.

The publication in 1989 of the comprehensive book Mozart's Symphonies: Context, Performance Practice, Reception by Oxford (Clarendon Press) further enhanced Zaslaw's reputation among music scholars. The London Times Literary Supplement praised Zaslaw as "a level-headed guide" and the book as "a major achievement [that] ... will not be superseded for many years, if ever."

In 1991, Zaslaw published The Compleat Mozart: A Guide to the Musical Works of Wolfgang Amadeus Mozart (Norton) with William Cowdery, another Cornell Ph.D. He intended the book, a collection of the program notes of each of Mozart's works that grew out of the bicentennial celebration, as a reference for the general listener and was surprised to learn that scholars and students all over the world are using it.

It's wrong to think of Mozart as the godlike creature he is sometimes portrayed as , Zaslaw says, because that trivializes him.

"Mozart knew he was good -- he brags about himself in letters to his father," Zaslaw relates. "However he didn't regard himself as in a different class from other musicians, but in competition with them." He was constantly revising his compositions, perfecting them in rehearsal and changing them to meet the talents of various performers. Far from merely transcribing the "voice of God," as legend has it, Mozart was a hard-working composer who struggled to find patrons, wrestled with debt, endured critics and was only all too human.

Which may be why his image, as well as his music, is still beloved.