Ronald Stevenson - composer, pianist, writer, scholar, broadcaster, lecturer, editor, teacher, transcriber, wit, and all-round renaissance man - is 70 today. From working-class beginnings in 1920s Lancashire, he has risen to become a key figure in 20th-century British music - latest of the great pianist-composers in a line going back to Grainger, Busoni and Liszt.

As a boy in Blackburn, it was his father's singing of Scots songs that first inspired him to compose, and also turned his thoughts northward, to the ancestral Scotland where he has lived most of his life, and whose music has been a central thread in his creative career. It also lit the spark of lyricism and melodic invention that characterises his musical language - a gift that won him no favours in the arid context of post- war "new music" but will surely come into its own again in these more relaxed postmodern days.

The early years were not easy. After studies at the Royal Manchester College, his composing career was interrupted in 1948 by imprisonment as a conscientious objector against National Service. It was then that Stevenson discovered some of the abiding influences and passions of his life: the poetry of Blake, for example, and the music of Busoni. A committed socialist and pacifist, he boasts a political awareness which, if never doctrinaire, has certainly affected his conception of the role of the artist in society.

After moving to Edinburgh in 1952, he joined the city's thriving literary- artistic life, soon becoming dubbed "The Laughing Cavalier of the Cafe Royal" (while his distinctive broad-brimmed hat and goatee beard also earned him the sobriquet of "Buffalo Bill" from his Edinburgh school-pupils).

Stevenson's early musical influences were particularly European in outlook, at a time when this was not typical of the average British composer. Along with the lyricism of song went a deepening interest in counterpoint, with Bach looming large; the pianism of composers like Chopin and Liszt added a strand, with the exuberant energy and open-air quality of Grainger chiming in later, while figures like Hindemith and Schoenberg had their place. But it was the discovery of a vocal score of Busoni's final opera Doktor Faust that produced what Malcolm MacDonald, author of the most recent book on Stevenson, calls "an immediate Joycean epiphany" - the recognition that here, in this music's "dark luminescence", he had found the voice of his "mentor in absentia".

Busoni's example, his belief in "the One-ness of Music", his interest in new musical languages but at the same time in building on the past, his combination of Germanic intellectual rigour with Italian lyricism and beauty, informed a series of works based on or inspired by the older master: the Prelude, Fugue and Fantasy on Busoni's Faust, the First Piano Concerto, A Faust Triptych, as well as a yet unpublished study of Busoni's life and works. And of course Busoni (whose works Stevenson has performed worldwide and whose piano stool now stands in his home near Edinburgh) was the virtuoso pianist-composer par excellence - exponent of what Bayan Northcott has called "the tradition of Philosophical Virtuosity".

As regards his own music, his most celebrated work so far is the great Passacaglia on DSCH, a tribute to Shostakovich based on the Russian's own musical motto. Premiered in Cape Town in 1963 (during a brief spell teaching in South Africa), this major work - a veritable world of music in itself, with its references to Scottish pibroch and African drumming - signalled an interest in non-Western music that was far ahead of its time. Taken up by John Ogdon, the Passacaglia was first heard in the UK at Aldeburgh - the start of a fruitful association that saw the commissioning by Britten and Pears of a song-cycle, Border Boyhood, in 1970.

Stevenson's prolific creative flow at this time included a second piano concerto, The Continents (which he premiered himself at the 1972 Proms), many Scottish-inspired works and a Violin Concerto for Yehudi Menuhin.

Coming as he did after the Britten/ Tippett generation and before the so-called Manchester School of Birtwistle, Maxwell Davies and Goehr, Stevenson's relation to the music of our time has always been problematical. His love for the musical virtues of melodic line, beauty of sound and contrapuntal coherence, and his constant allegiance to tonality (albeit frequently using 12-tone techniques) do not link him to the post-war axis of cerebral modernism. Now that the latter is taking on a distinctly historical aspect, it can be seen that Stevenson has paved the way for much of what a new generation of composers are doing today. Figures like James MacMillan, Edward McGuire and William Sweeney do not have to do for Scotland what Bartok did for Hungary - Stevenson has done it for them. As he says himself, "Scotland and Ireland have a live folk tradition... On the examples of Bartok and Kodaly, and especially Grainger, Scots composers will begin to write music that is national and international". They have, and it is.

Stevenson always has been a fighter - not in the violent sense of the term, of course, but in Blake's sense of "mental fight" - for peace, truth and musical integrity. The true significance of his work can only become more apparent in the future. And that future starts now.

Ronald Stevenson Society: fax 0131 229 9298; e-mail: RSSoc@