This documentary by Christopher Nupen features revealing interviews with Williams, a glimpse into his collaborative process with composers Stephen Dodgson and Patrick Gowers, and a jaw-dropping 1971 concert from Ronnie Scott’s, the legendary Soho jazz club. Williams, who chafes at the rigidity of the classical milieu, has made his career breaking down boundaries between classical music and other genres: he has worked consistently with jazz musicians and rock stars, like Pete Townshend of the Who, and even achieved Top 20 chart success with Stanley Myers’s “Cavatina,” the theme of The Deer Hunter.