These arrangements of easy- to medium-level duets by 18th- to 20th-century masters are great for instruction and for fun because the pieces are short and easy to master. With works by Mozart, Bartk, Boismortier, Kabalevsky, Couperin, Glazunov, Schumann, Shostakovitch, Purcell, and Bach, it’s a survey of music history for young students.