Classical. The Five Divertimenti K. 439b consists of 25 pieces originally scored for two clarinets or basset horns and bassoon. It is assumed that Mozart wrote these works for the Stadler brothers, Anton (famous for the Clarinet Concerto) and Johann. Originally scored in C major (Mr. Sauer has arranged them in keys that are more suitable for the trombone), the 25 pieces were grouped into five movements each. The styles of the movements include Sonata-allegro, Minuet and Trio, Larghetto, Adagio, Rondoand even a Polonaise. This collection of the Five Divertimenti is an immense amount (about 45 minutes and 120 pages total) of entertaining music, all arranged by Ralph Sauer for three advanced trombonists. -the publisher