Our guests this week include Stuart Duncan, a Grammy-winning American bluegrass musician who plays not only the fiddle but also mandolin, guitar, and banjo - and he sings vocals. He has performed with Diana Krall, George Strait, Dolly Parton, Guy Clark, Reba McEntire, and Barbra Streisand, among many others. A longtime member of the Nashville Bluegrass Band, he most recently collaborated with Yo-Yo Ma, Chris Thile and Edgar Meyer for album called "Not Our First Goat Rodeo, a followup to their 2011 "Goat Rodeo Sessions" album. Stuart will play "The New Democracy," which can also be heard on the Nashville Bluegrass Band's 1991 album "Home of the Blues."   Kaylah Walker, 14, from Virginia Beach, Virginia, a violinist whose teachers have included Christina Morton and Jeannie DeDominick. A winner of several concerto competitions, Kaylah is also involved in musical theatre, having been cast in lead roles in the Wizard of Oz and The Addams Family at her school, Cape Henry Collegiate. She will play the first movement of de Beriot's Concerto No. 7 for Violin.  The Stars Aligned Siblings - a very young quartet from San Pablo, Calif. Members are all siblings from the Breshears family: violinists Dustin, 13, and Valery, 11; cellist Starla, 12; and violist Colin, 8. Their teacher is Ayke Agus, who has been schooling them in the traditions of her own teacher, Jascha Heifetz. The siblings have already taken their show on the road, touring  United Kingdom, Argentina, Mexico, and in the United States and appearing in festivals, broadcasts and competitions, where they have won numerous awards. They will play the first movement of Beethoven's Quartet, Op. 18, No. 6.