As a life-long fan of Williams' film music, I have only recently discovered his more "serious" pieces. Like many versatile composers before him (think Korngold, Waxman, etc.), Williams is able to function in both worlds, writing rousing, effective scores and introspective, yet extremely dynamic works for concerto and orchestra.
Gilbert "Gil" Scott-Heron was an American soul and jazz poet, musician, and author, known primarily for his work as a spoken word performer in the 1970s and '80s. His collaborative efforts with musician Brian Jackson featured a musical fusion of jazz, blues, and soul, as well as lyrical content concerning social and political issues of the time, delivered in both rapping and melismatic vocal styles by Scott-Heron. His own term for himself was "bluesologist", which he defined as "a scientist who is concerned with the origin of the blues." His music, most notably on Pieces of a Man and Winter in America in the early 1970s, influenced and helped engender later African-American music genres such as hip hop and neo soul.
This is undoubtedly the equivalent of Gilberto Gil "Unplugged" – Gil, his acoustic guitar, and a nonelectric five-piece band recorded live in a studio – and it is a thoroughly musical triumph as Gil mesmerizes his attentive audience for some 74 minutes. He starts out with the nearly pure reggae of "A Novidade," but before long, he establishes himself in a mostly consistent, loping set of intimate grooves thoroughly rooted in Brazil. Gil had a hand in writing all of this tuneful material except Anastacia Dominguinhos' "Tenho Sede," Caetano Veloso's "Sampa," and a left-field choice, Stevie Wonder's "The Secret Life of Plants," which lends itself very well to Gil's bossa nova approach and proenvironmental position. It is not a complete live portrait of Gil, though; the astounding quickness and flexibility of his voice is fully vented only toward the end of the concert. The later Quanta Live album will give you a wider panorama of Gil's range.