Metamorphosen, Study for 23 Solo Strings, subtitled "In memoriam",  is a composition by Richard Strauss, scored for ten violins, five violas, five cellos, and three double basses. It was composed during the closing months of the Second World War, from August 1944 to March 1945. Strauss dedicated it to Paul Sacher. It was first performed in January 1946 (by Paul Sacher and the Zürich Collegium Musicum).
It is widely believed that Strauss wrote the work as a statement of mourning for Germany's destruction during the war, in particular as an elegy for devastating bombing of Munich, especially places such as the Munich Opera House. This view, which began in the late 1940s, was supported and strengthened by a 1951 study, although Strauss, who died in 1949, never said what the piece was about. A differing view was published in the 1990s by Timothy L. Jackson who, after a careful analysis of sketch materials, concluded that Metamorphosen was a philosophical, Goethean study of the underlying cause of war in general; the cause being the bestial nature of humankind. Jackson's view is that in Metamorphosen Strauss used the classical concept of metamorphosis as a process of transcending from the mundane into the divine, but inverted it such that the outcome of metamorphosis is not an attainment of the divine but rather a descent into bestiality. Another 1945 piece, München, is clearly a memorial for Munich and scholars have associated the sketches of München with Metamorphosen since the 1950s. Jackson argues that scholars have assumed the early sketches of München were the basis for Metamorphosen based on weak, even untenable assumptions. This new view has gained some acceptance, although the view of Metamorphosen as an elegy for Munich is still widespread.
Near the very end of the piece, several bars of the funeral march theme from Beethoven's Eroica Symphony are quoted explicitly in the bass part, accompanied by the words "In Memoriam!" in the score. The Eroica theme is motivically related to the main themes of Metamorphosen, but Strauss wrote that the connection did not occur to him until he was almost finished. There are several theories about how and why Strauss quoted Beethoven, and who or what "in memoriam" refers to. In 1947 the critic Matthijs Vermeulen claimed the whole piece was an elegy for the Nazi regime, and "in memoriam" referred to Hitler himself. This theory was quickly and strongly denied by Willi Schuh, who had been involved with the work from the beginning. Schuh claimed that "in memoriam" referred not to Hitler but Beethoven, and most scholars since then have supported this idea. Another theory involves Beethoven's Eroica having originally been dedicated to Napoleon but after Beethoven's disillusion with Napoleon rededicated "to the memory of a great man", while Napoleon was still alive and in power; Strauss's quotation of the Eroica and writing "in memoriam" can be seen as having interesting parallels with Strauss's own involvement and rejection of Hitler and the Nazi regime. Beethoven had ironically "buried" and memorialized the still-living Napoleon. Strauss could have been pointing to a famous precedent for his own rejection of a tyrant he had once supported. Against all these specific theories is the fact that Strauss was fond of oblique references and multiple layers of meaning and connotation. Strauss may have considered the quotation and words "in memoriam" as having many meanings.
As one of Strauss's last works, Metamorphosen masterfully exhibits the complex counterpoint for which the composer showed a predilection throughout his creative life.
- Verschaeve, François (2007). What's what in titles of classical music-- and beyond: a dictionary of titles. p. 236. OCLC 555100941isbn=978-0-9738454-1-9. Retrieved 22 October 2011.
- Jackson, Timothy L. (1997). "The Metamorphosis of the Metamorphosen: New Analytical and Source-Critical Discoveries". In Bryan Gilliam. Richard Strauss: new perspectives on the composer and his work. Duke University Press. pp. 193–242. ISBN 978-0-8223-2114-9. Retrieved 19 October 2011.
- Schmid, Mark-Daniel (2003). The Richard Strauss companion. Greenwood Publishing Group. p. 222. ISBN 978-0-313-27901-0. Retrieved 19 October 2011.