Music: Like I Do

The Toscanini-trained musicians of the NBC Symphony Orchestra blinked, then stared: Was it Frank Sinatra? At first glance, the boyish-looking, new guest conductor was a dead ringer for Frankie: wispy, wire-thin, sallow-cheeked and dark-haired. But when 28-year-old Guido Cantelli stepped to the podium and rapped his baton, the jokes stopped. By the time Guido had driven them through bar-by-bar rehearsals of Hindemith and Haydn without looking at a score—gesturing and singing fa-sol-la-tis to make up for his lack of English—musicians were murmuring about "terrific talent."

Cried one hoarse but happy observer—Arturo Toscanini—as he shuffled from his aisle-seat listening post in Studio 8H:...