Ferruccio Busoni’s remarkable Piano Concerto from 1904 may be the longest concerto ever written for any instrument. It may also be the most challenging. It demands nearly superhuman stamina and virtuosity of its soloist. The impetus for these performances may have come less from audiences, to whom Busoni is hardly a household name, than from the musicians themselves, to whom a monumental work like the Busoni concerto presents an exhilarating challenge. Yet the Cleveland audience was raptly attentive and cheered the musicians to the echo. At a moment when adventurous twentieth-century repertoire seems to be vanishing from symphony programs, the Cleveland Orchestra is to be applauded for mounting this singular work.