Mansfield took up the ukulele in 2007, after his cancer made it too difficult for him to play the violin. He appreciated the instrument's light weight and ease of play, and was drawn to its percussive quality: A ukulele can set the beat, and that's what it does in "Blue Skies." Mansfield's mom was originally scheduled to sing the song, as she had done many times with her son while he was entertaining fellow patients at the National Institute of Health. But Mansfield and his friends had many music-business connections. So the vocalist is Manhattan Transfer's Laurel Masse, whose luscious chops are complemented by a jaunty clarinet and mellow, slightly melancholy bass line, all part of an arrangement that Mansfield himself cooked up. But, really, his ukulele is what propels the song; it's the insistent sound of a young man who, as his mother remembers, loved playing music for people and believed that as long as you're alive, you might as well look on the bright side.