In the heyday of the touring virtuoso, when fluffy-haired young pianists such as Franz Liszt and Sigismond Thalberg made maidens swoon with a maelstrom of double octaves, the live performance was the only criterion of brilliance. With the advent of recording, this all changed. Sergei Rachmaninov was perhaps the first pianist to become better known for his recordings than for his concerts, as his early discs for RCA Victor were played in drawing rooms from Milwaukee to Melbourne.

Since then, a pianist’s recordings have come to be regarded as their chief artistic testament. (With characteristic maximalism, Glenn Gould took this trend to its furthest point in the late 1960s, giving up live concerts and claiming he preferred the sound of...