ON Feb. 1, Mstislav Rostropovich and the National Symphony Orchestra will give the world premiere of my "Pied Piper Overture." If anyone had told me a few years ago that I would compose not one but three pieces of music based on the "Pied Piper of Hamelin," I would have considered it a rather poor joke. As a composer of serious symphonic works and dramatic operas, the idea of setting a children's tale to music was the farthest thing from my mind.

Often, however, the works of a composer are governed by unusual circumstances. My three "Pied Pipers" are no exception.

It started seven years ago when Antal Dorati and the NSO gave the premiere of my "Ariel" Symphony, based on the poems of Sylvia Plath. These poems, beautiful though they are, deal with iron lungs, concentration camps and mental disintegration. They were written shortly before Plath's suicide at the age of 31, hardly a children's story. Subsequently this work was played in Carnegie Hall and shortly thereafter was recorded by the Syracuse Symphony Orchestra. The recording was the first by an American Orchestra on Peter's International label. Pierre Bourdain, then with Peter's, invited me to lunch at a Japanese restaurant in New York with his friend, Bobbie Finn. Finn was a former student of the great flutist Jean Pierre Rampal. For some years she had been toying with the idea of a work for narrator, flute and orchestra based on "The Pied Piper," but could not find the right composer for the project. Over sushi and plum wine, Bourdain told me he had played the recording of "Ariel" for her and that she decided I was the man for the job. Rampal agreed and so was born Pied Piper No. 1.

In the meantime, Wolf Trap had produced my opera based on John Webster's "Duchess of Malfi" and Jouette Shouse had asked me to follow it up with an opera for children. During the next few years, however, I had no time to think about this project since I was writing an orchestration book for Prentice-Hall, fulfilling several orchestral commissions and teaching full time at George Mason University. As I began work on the Rampal Piper, it suddenly occurred to me that the Piper subject was ideal for a children's opera. Piper No. 2 tentatively is scheduled for production at the Burns at Wolf Trap this summer.

As all this was going on, Mstislav Rostropovich heard the "Ariel" recording, played for him by Henry Fogel, who produced it. Rostropovich liked the work enough to commission a new piece for the' NSO. After some weeks of fruitless work on an orchestral tone poem which never seemed to gel, the tunes I had composed for the Pied Piper began to run through my mind in an entirely new context, and a concert overture began to write itself almost without my conscious volition. I sketched it out in about 10 days. The scoring and orchestration took four weeks. So was born Pied Piper No. 3. It is this work that Rostropovich and the NSO will premiere in February. In March, Hugh Wolf will conduct the Pied Piper with the Louisville Orchestra and Rostropovich will conduct it in four capitals of the Far East during the NSO's spring tour.

The "Pied Piper Overture" is a piece of pure fun, a light, lively concert overture in the tradition of Bernstein's "Candide Overture" and other works in this genre. It is meant to have no profound significance, but to entertain and delight. Certainly, it was a joy for me to write. After Plath's lugubrious poetry and Webster's dark Jacobean tragedy, it was time for a change. Sometimes a composer just has to have some fun.