Richard Strauss's tone poem Also sprach Zarathustra is one of his most controversial works, but it is also one of the staples of the virtuoso orchestra. Its greatest popularity has been achieved in recent years with its association with Kubrick's film 2001--A Space Odyssey. This guide examines the intellectual background of the work and considers the ways in which it has been received by composers and writers. It also discusses the musical background of Liszt and Wagner which gave rise to the genre "tone poem," and provides an analysis of several aspects of Strauss's musical language.