Maestro Zander, as everyone has long known, is a renowned conductor of the music of Mahler. His love affair with the composer began with the entrancing, sun-filled, playful, and sublime Fourth Symphony. In the final movement the soprano soloist must sing with the voice of a child, which has proven elusive for even the greatest artists. But Claire Booth, an English soprano with a staggering range of vocal expression, is a rare hybrid: a soprano who can produce both the rich tones and deep autumnal sensibility of Strauss's Four Last Songs and the crystalline lightness of the Mahler Symphony No. 4.