OLIVIER MESSIAEN ( 1908-92) was one of the most influential composers and teachers of the 20th century, not just within France but internationally. He is noted for inventing new techniques of organising musical materials such as pitch and rhythm, but is also remembered for his lifelong love of birdsong. Many of his greatest works combine visionary Christian mysticism with the songs of birds, whom Messiaen regarded as superlative and divinely created musicians.