By the mid-60s Gould had become one of the most talked-about and written-about living pianists. "His provocative musical ideas, backed by complete integrity of purpose and thorough academic understanding of the technical workings of a piece, make him either a musical Devil's Advocate or enfant terrible, depending upon your point of view."7
Gould's mature period saw two major compositions: the String Quartet, Op. 1 (there was no "opus 2") and the lighthearted So You Want to Write a Fugue?. The latter piece was written for The Anatomy of the Fugue for the CBC-TV Festival program, broadcast on March 4, 1963. It is a piece of considerable "learnedness".
His creativity also found an outlet in cadenza writing: his Cadenzas to the Concerto No. 1 in C Major for Piano and Orchestra, by Beethoven, Op. 15, was almost an original composition. He also made piano transcriptions for works by Wagner, Ravel, Richard Strauss and other composers.
Gould, Glenn. So You Want to Write a Fugue?. New York: G. Schirmer, 1964
Gould, Glenn. Cadenzas to the Concerto No. 1 in C Major for Piano and Orchestra by Beethoven, Op. 15. Great Neck, New York: Barger & Barclay, 1958
Gould, Glenn. String Quartet, Op. 1. Manuscript score, April 1953-October 8, 1955
Glenn Gould, facing a string quartet on stage in an empty hall, with parts for his String Quartet, Op. 1 on the music stands. 196?
Glenn Gould, Howard Scott and a CBS recording engineer, listening to tapes of the String Quartet, Op. 1., n.d.