Composer Steve Reich turns 70 next month, and he has never been more in demand as a musical figurehead. “Reich may be an acclaimed cultural figure now, but at the beginning he was a revolutionary… He happily reclaimed the harmonies that the Western world had found sufficient for centuries; indeed, he looked back further to medieval music, as well as to Hebrew chant, and Balinese and African percussion traditions… And this was so controversial that, during the first 10 years of his ensemble, most of the performances of Reich’s music were in art galleries and museums, not concert halls.”