At best, a record label is a commercial expression of a coherent musical aesthetic. Ergo Nonesuch, launched in 1964 as a budget-classical imprint of Elektra Records. From 1965-79, the label was run by Teresa Sterne, who championed modern composers such as Edgard Varèse, Elliott Carter and George Crumb, along with essential Americana, such as ragtime composer Scott Joplin (a Joplin piano disc on Nonesuch by Joshua Rifkin ignited the ragtime revival in 1970), Stephen Foster and Charles Ives. Under Sterne’s aegis, Nonesuch’s Explorer Series pioneered the marketing of what came to be known as world music, with discs ranging from Javanese gamelan to Bulgarian voices. This magnificent two-CD set features Sterne on one disc, as a young pianist, playing Bach, Mozart, Liszt, Rachmaninoff and Dutch composer David Broekman; the second disc compiles gems from the Sterne-era Nonesuch and Explorer catalogs.