THE LIBRARY of Congress will present an unusual program of English poetry and music on Monday and Tuesday.

On both evenings, Paul Callaway will conduct music By Delius, Britten and Vaughan Williams, leading up to a finale of Sir William Walton's most-famous work. "Facade." Hermione Gingold and Russell Oberlin will read Edith Sitwell's high-spitirted poems.

The program will be played on Monday for an invited audience and will be repeated Tuesday for the public.

"'Facade' is my first name," Walton, who will be 75 on Tuesday, told an interview in 1963.

"'Facade' was a sort of freak. Usually I work jolly hard at composition; I prefer to have the time to look around. But 'Facade' was written in three weeks and I never thought much about it as much than a couple of evenings' entertainment.

"An entertainment" is the official description of the unique work created by the combination of Edith Sitwell's poems and Walton's music. Its first performance was private, in the Carlyle Square home of Sacheverell and Osbert Sitwell in London. Walton had met Sacheverell at Oxford, an institution both young men left at age 16. (Walton flunked algebra in his first major examination there, a minor matter Oxford repaired 24 years later in awarding the composer an honarary doctorate in music.)

Edith Sitwell has told how "Facade" came to be written. "At that time," it was in 1921, "Sir William was sharing a house with my brothers," she wrote, "so he and I worked, it might be said, together, and he, my brothers and I discussed the work together in all its stages. There were, at first, difficulties about presenting it, because it was impossible for the speaker's voice, unaided, to be heard above the sound of the instruments. My brother Osbert, therefore, who stage-managed the performance, and who was, indeed, responsible for the inception of the work, suggested that the wirter should speak through a megaphone. And, because this would look ugly, and, too, in order to deprive the work of any personal quality (apart from the personality interest in the poems and music,) and he suggested the performance should take place from behind a curtain."

The megaphone, incidentally, was something called a "Sengerphone," named after its ventor, who used it when singing the role of Fafner in Wagner's "Siegried." The curtain was decorated by a huge head painted by Frank Dobson.Through the head's large mouth, the megaphone gave the speakers the necessary projection.

While "Facade" may be Walton's best-known and most-often performed work, his total repertoire includes an impressive number of successful scores in many idioms. Of the concertos, one each for violin, viola and cello, the first is the finest and best known. Each, however, had distinguished progenitors. It was Sir Thomas Beecham who suggested that Walton should write a viola concerto for Lionel Tertis. When the famed British violist sent the score back by return mail, Walton conducted its world premiere with no less than Paul Hindemith as soloist. The violin concerto was commissioned by Jascha Heifetz who used to give what still stand out as perhaps its greatest performances; the cello concerto was commissioned by the late Gregor Piatigorsky who played its premiere.

After "Facade," however, it is not a concerto but Walton's only big choral machine, "Beishazzar's Feast," that is undoubtedly his most popular achievement. From the moment of its premiere at the Leeds Festival in 1931 under the baton of Sir Malcolm Sargent, "Belshazzar's Feast," has been one of the staples of the world's crack choral groups. With its oversized orchestra, its Old Testament text augmented by Osbert Sitwell, and its extended baritone solo, a part of which is unaccompanied, it is an exciting test for singers and players, a sure-fire crowd-pleaser for audiences.

Walton has never been a prolific composer.Somewhat in the manner of Samuel Barber, his junior by about eight years, Walton has written only when a specific stimulus appeared whether from exterior or interior sources.

His one full-length opera, "Troilus and Cressida," has never received the wide public acclaim to which its superb music and text fully entitle it. While it has been heard in Europe and this country, it may be only in the near future, thanks to te impact of its first full-length recording, with Janet Baker as Cressida, that it will find a large public.

Walton has been more successful in one special area than almost any other living composer. In his music for three of the great Shakespearean films featuring Sir Laurence Olivier - "Hamlet," "Henry V" and "Richard 111" - Walton composed on a lofty plane of musical excellence from which he never seemed to have to depart to make the slighest concessions to the exigencies of writing for the medium. His singular gift inspired him to remarkable music over which Olivier speaks his "To be or not to be" soliloquy. No less moving is the touching sound of the passacaglia that accompanies the death of Falstaff.

There are two Walton symphonies written 25 years apart.One of music's most famous anecdotes dates from the U.S. premiere of the first of these, whichtook place Chicago in the season of 1935-36. Sir Hamilton Harty, the brilliant Irishman who had conducted the world premiere of the symphony in London in November of 1935, brought the work with him when he appeared as guest conductor of the Chicago Symphony.

At the Thursday night concert when the work first played, Harty could not help noticing the steady exodus from Chicago's Orchestra Hall, a parade that started shortly after the symphony began and continued through out most of its four movements. The next day the word got around that something was probably going to happen at the Friday afternoon repetition of the concert, especially since symphony orchestras' matinee audiences are notoriously uninterested in new music, if, indeed, in music at all.

In any case, a number of us students from the University of Chicago zapped down to the hall to hear the program. And sure enough. After intermission, when it was time for the Walton, Sir Hamilton turned around on the podium. Glaring at his listeners for a moment, the fiery musician finally said, in tones dripping with sarcasm, "We will not twice cast pearls before swine! We will play the Symphony from the New World!" And they did.

There is a rewarding list of "smaller" works from Walton's pen, all of them brightened by a special brand of sophistication: Among then the "Scapino" Overture is a gem, as are the stylish transcriptions of Bach that Walton did for Frederick Ashton's ballet, "The Wise Virgins." His only string quartet is cruelly neglected. But what we deserve most of all to hear and never do is elegant charm to the song cycle," "A Song For the Lord Mayor's Table," commissioned by the Worshipful Company of Goldsmiths in London. It was given its world premiere by ELizabeth Schwarzkopf and Gerald Moore. Surely a recording of that is floating around somewhere. It would be a rich trove.

For all that Walton worked with fastidious taste, another characteristic he shared with Barber, his music is, in every idiom, large in feeling, and basically, at least for today's audiences, middle-of-the-road in stlye. Giventhe chance, it is likely to attract listeners.

The Library of Congress is showing the most welcome imagination in offering this week's celebration of Sir William's 75th anniversary.