Wikipedia
Kammermusik'' (Chamber Music'') is the name given to a series of eight musical compositions by the German composer Paul Hindemith.
Written between 1921 and 1927, the first two works (Kammermusik No. 1 and Kleine Kammermusik — Little Chamber Music) are for small ensembles (12 piece and wind quintet respectively), and share the opus number 24. Kammermusik No. 2 to Kammermusik No. 5 (Opus 36) are for larger ensembles and are concertos. The final two works form Opus 46.
As Calum MacDonald notes, the majority of the works are not 'chamber music' in the traditional sense of the word, as they require larger forces than normally understood by the term. Indeed, six are effectively concertos (Hindemith's subtitles say as much). However, in contrast to the much larger forces (and sounds) Hindemith previously employed, the works are very much chamber-styled if not truly chamber works.