Music : How to Tune In to Mozart--With Your Good Ear : <i> Interested in learning more about music? This column is another in an occasional series devoted to books that can help make you a more perceptive listener. </i>

Robert Harris’ “What to Listen for in Mozart” (Penguin paperback: $12) is the single best introduction to all classical music and most useful I know of for a curious amateur who longs to know more about the subject.

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Harris’ title might be a bit confusing because of its similarity to Aaron Copland’s splendid “What to Listen for in Music” (Mentor paperback: $5.99). But Copland, with his composer’s enthusiasm, covers a wider field and deals mostly in generalities and sometimes arcane samples. Harris, a CBS radio executive who produced a series of music documentaries, focuses solely on a few Mozart scores and goes right to the nitty-gritty details of how the compositions are put together.

The first movement of Mozart’s “Eine Kleine Nachtmusik” serves as the starting point. Harris, writing an impressively informed first book, teaches you how to read the score. Then he goes over the same opening section (technically called the exposition) again and again from different points of view, looking at its rhythms, phrase structures, harmonies and the large formal structure.

You learn how all these elements converge to reinforce each other.

If this sounds scary and forbidding, relax. Harris writes in an easy, reader-friendly style, alerting you to any difficulties ahead and urging you to take necessary time out to understand.

He wants you to listen to the music, and his object is to show you how to enjoy the stuff.

“It would take a sociologist to sift through the layers of elitism and snobbery that have accumulated on the clear, brilliant surface of classical music,” he writes in his introduction. “The composers who labored long and hard to communicate as simply and directly as they could to their audiences would be astonished, if not furious, at the treatment their art receives today.”

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Harris makes good on his promises. He starts you out tapping the basic meter of the piece while clapping the differing rhythms of the musical phrases. You learn how much rhythmic variety Mozart packs into these passages and how balanced and symmetrical they are but also how different so as to avoid monotony.

With the melodic phrases--the little (usually four-bar) statements out of which Mozart builds the piece, he puts “10 separate musical ideas in the first two pages, in music lasting less than 90 seconds,” Harris writes.

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And Mozart devotes exactly the same care to the harmonies he uses.

One of the book’s most valuable lessons is its explanation of the critical shift from the tonic to the dominant--the major dramatic event in sonata-allegro form, the form most classical first movements are written in. Thanks to Harris’ elucidation, you will hear this shift clearly and easily.

Music students probably learn all this somewhere along the line early in their studies, but others have to flounder about or just ignore all it. Their loss.

The author also takes some time out to show how Mozart was dealing with a universal musical problem: how to balance similarity (to create musical coherence) with surprise (to avoid monotony). He shows how Gershwin faced and solved the same problems in writing his hit tune “I’ve Got Rhythm.” Yep, you’ll appreciate Gershwin more after reading this book, too.

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Harris takes similar looks at the “Haffner” Serenade, the K. 467 Piano Concerto (called here the “Elvira Madigan” Concerto after its use in the 1967 Swedish film) and, in greater detail, the “Jupiter” Symphony.

The “Elvira Madigan” title rankles many serious music lovers, however. Not everyone saw the film in its heyday. It may be a great movie, but it doesn’t seem to surface very much in revivals or film buffs’ conversations these days. Ironically, linking it to Mozart’s score may have given the movie a classic stature and immortality it would not have achieved on its own.

Harris also discusses librettist Lorenzo da Ponte’s three operas (“Marriage of Figaro,” “Don Giovanni” and “Cosi Fan Tutte”) and “The Magic Flute.” He ends with a list of Mozart’s 50 best compositions, which, of course, is an arbitrary number and inevitably a debatable selection, although anyone’s top Mozart 50 will include many of the works he mentions.

Relevant parts of the scores are included in the book, so you don’t have to buy anything else and flip back and forth. But after reading it, you’ll probably want to buy some of the full scores to apply his lessons on your own.

“Are we supposed to hear all this subtlety under the surface of Mozart’s music?” Harris asks. “Must we hear all of this to fully appreciate his works?” The answer is yes, and no.

“Some of these effects Mozart clearly wanted disguised; other he probably hoped his listeners would hear. Like the man himself, Mozart’s music always remains somewhat mysterious. He took such pains in his art, almost unbelievable pains, to create the most satisfying and rewarding music for us, his listeners, yet he hid away some of his most beautiful effects behind veils of subtlety and reserve.

“The more we can pierce some of those veils, without losing sight of the surface that Mozart so lovingly created, the more we can hope to understand the true significance of the extraordinary art this great man created.”

Chapters of biography alternate with chapters of musical analysis. The biography is generally sound, although scholars are still debating various questions such as how poverty-stricken was the composer in his final years and what killed him.

The quotations from Mozart’s letters suggest his propensity for scatological humor. At the same time, his uncharacteristically voiced depression resonates in a letter he wrote in his final year to his wife, Constanze, who had stayed at Baden, where he had taken her for its famous medicinal baths:

“You cannot imagine how I have been aching for you all this long while. I can’t describe what I have been feeling--a kind of emptiness, which hurts me dreadfully--a kind of longing, which is never satisfied, which never ceases, and which persists, nay rather increases daily. When I think how merry we were together at Baden--like children--and what sad, weary hours I am spending here! Even my work gives me no pleasure, because I am accustomed to stop working now and then and exchange a few words with you.

“Alas! this pleasure is no longer possible. If I go to the piano and sing something out of my opera, I have to stop at once, for this stirs my emotions too deeply. Basta! The very hour after I finish this business I shall be off and away from here.”

The opera he refers to is the sublime and simple “Magic Flute.”

* The Los Angeles Music Center Opera will present Mozart’s “Don Giovanni” Sept. 27-Oct. 14 at the Dorothy Chandler Pavilion, 135 N. Grand Ave., Los Angeles. $21 to $115. (714) 740-2000 (Ticketmaster) or (213) 972-0777. Opera Pacific will present “The Magic Flute” March 11-24 at the Orange County Performing Arts Center, 600 Town Center Drive, Costa Mesa. $18 to $85. (714) 740-2000 (Ticketmaster).