The name Kroll has a distinctive ring in clarinet circles as Oskar Kroll’s book on the clarinet has been regarded as one of the standard treatises on clarinet playing ever since its first edition in 1944.Karl Kroll (1881-1957) - father of the author Oskar and teacher of the editor Dieter Klöcker - enjoyed a considerable reputation as a clarinettist during his lifetime.The '20 Caprices' are short pieces, musically indebted to the late Romantic period, but incorporating a number of tricky fingerings.