George Enescu's violin playing is the stuff of legend, but he saw himself mainly as a composer. So why do we know so little of his unique music? By Dominic Saunders

George Enescu was the man described by Yehudi Menuhin as "the Absolute by which I judge all others... the most extraordinary human being, the greatest musician and the most formative influence I have ever experienced."

Today, Enescu is remembered as one of the greatest violinists of the 20th century, and as Menuhin's teacher and mentor; he was also a formidable pianist and conductor. During the course of his extraordinary life he played to Brahms, studied with Fauré and Massenet, and knew Bartok, Strauss, Ravel, Debussy and Shostakovich. Pablo Casals, whom he accompanied on the piano, called him "the greatest musical phenomenon since Mozart".

Yet Enescu saw himself as first and foremost a composer. Which begs the question: why is his unique and beautiful music not better known? Why did his favourite among his own works, the opera Oedipe, have its first British performance only this summer, over 60 years after it was written? Why has a work as significant as the Piano Quintet Op 29 waited until tonight for its UK premiere? (The Solomon Ensemble, of which I am the pianist, will give it.)

The answer embraces both the political and the personal: the postwar divisions of Europe, the many setbacks and difficulties he experienced during his lifetime, and his modesty and complete lack of interest in self-promotion. One wonders how he would fare in the current era of marketing and PR.

Six or seven years ago I knew none of his music, until my friend and colleague the violinist Anne Solomon sent me a recording of his Third Violin Sonata. I was astonished by it, and since then have become more and more fascinated by and passionate about his music. Anne and I started working together on the violin and piano pieces, rehearsing and including them in concert programmes, and were thrilled when, in the run-up to a recording, Menuhin agreed at the end of 1997 to hear us play and offer his advice.

Enescu's scores are filled with more detailed markings and instructions than I have come across almost anywhere else - every nuance of technical and expressive detail is there on the page, and the effect on the performer of the sheer volume of information can be overwhelming and even counterproductive at first.

One has to absorb all of this - the tiniest fluctuations of speed, fingerings, bowings, colours - until it becomes completely natural, and then the music can come alive in a way that is not complex or studied to the listener, but, rather, fluid and improvised-sounding. Time and again Menuhin referred us back to the myriad markings in the score and showed that it was enough to follow them all to the letter for the music to speak. He showed us photos and shared memories - apparently Enescu called him "my old young friend" - and the reverence he still felt for his former teacher 30 years on was obvious.

Enescu was born in 1881 in Moldavia in northern Romania, and, as the only one of 12 children to survive beyond infancy, must have seemed almost blessed from the start. First violin lessons came at the age of four from a Gypsy fiddler who taught him to play by ear. Soon afterwards he was writing his own pieces, and at seven he became only the second child under the age of 10 ever to be accepted by the Vienna Conservatoire. At 13 he moved on to Paris. Enescu's music may be little- played in western Europe, but in his homeland he is venerated as a figure of enormous importance - not just as their greatest composer, but for the way he promoted other Romanian musicians and raised huge amounts of money for philanthropic causes.

Music was such an innate part of his being that Enescu had the extraordinary ability to conceive and retain whole pieces in his head before writing anything down. Shortly before his death in 1955 he said to his friend Marcel Mihalovici: "If I could put down on paper everything that I have in my head, it would take hundreds of years." And it was not just his own music that he was able to absorb (I think "memorise" would be the wrong word) so completely in this way. In 1927 the 10-year-old Menuhin witnessed an event that has become famous. Ravel arrived with his new violin sonata and asked Enescu to go through the piece with him. After playing through the score just once, Enescu closed his part and they repeated the performance with the violinist now playing the entire work from memory.

Five years ago, when I first found Enescu's Piano Quintet in a list of his works, I was surprised to come across a major 40-minute chamber work from his mature period that was so little-known outside Romania. In fact he never quite finished editing the piece - though every note was there on the page - and it was neither published nor performed during his lifetime.

My colleagues and I were apprehensive, but when we were finally able to get hold of the parts it turned out to be music of incredible sensuousness and vitality. Enescu had such an acute ear for the different colours he could draw out of every instrument that he achieves effects of an almost orchestral richness.

Like all his most characteristic music, the writing is influenced at a deep level by the first tunes he had played as a child - the folk-music of his native country. The second movement of the Quintet has the exuberance and passion, and the first movement the melancholy, that Enescu felt to be the most characteristic moods of Romanian folk-music. (In the Third Violin Sonata, Menuhin described this mood to us as "nostalgia, yearning, resignation and intense sadness.") Learning the piece has been challenging and fascinating.

Throughout his life Enescu continually returned to old pieces, revising and retouching. But it is not just this fastidiousness that explains why we are left with only 33 pieces. Again and again he was frustrated in his desire to devote more time to composition. When the Romanian economy collapsed during the first world war, all his savings vanished and he was forced to return to the concert platform and resume a heavy touring schedule: the same thing happened again in 1946 when he chose to leave communist Romania - the last nine years of his life were to be spent in exile. By this time he was suffering from the spinal condition that was eventually to cripple him, but once again he had to return to performing, mostly as a conductor.

In his 30s Enescu had fallen in love with Marie Cantacuzino, known to her friends as Maruca, and a princess through her first marriage into one of the richest families in Romania. After she married Enescu she seems to have become more and more eccentric and difficult, if not actually mad in the end.

In the last few months of his life, when the pair were living in relative poverty in a dingy two-room apartment in Paris, she began to sell off his manuscripts and eventually even his Guarnerius violin. Menuhin and his wife Diana visited him there, and sat with him in a room just big enough for his bed and a grand piano.

Describing the scene, Diana later wrote: "Yehudi talked to him of music, and at one point Enescu turned to the piano and ran his sadly twisted hands over it as though it were an extension of his own being... I noticed the frayed tie, the shabby jacket, the waxen face with its clean, beautiful bones and serene eyes... " It is a deeply moving picture of a man utterly devoted to music whose life ended tragically. His music deserves a better fate.