The volume opens with something unusual: opus 42 is a single work, short and surprisingly easy to play; Haydn described it as "something small and with only 3 pieces". The Quartets op. 50, including the so-called Frog Quartet, are dedicated to the Prussian king Friedrich Wilhelm II, who was a talented cellist. Even though the "solo" at the beginning of opus 50,1 is meant as joke, there are some good passages for cellists.