Frédéric Chopin's Fantaisie-Impromptu in C♯ minor Op. posth. 66 is a solo piano composition. It was composed in 1834 and published posthumously in 1855 despite Chopin's instruction that none of his unpublished manuscripts be published. The Fantaisie-Impromptu is one of Chopin's most frequently performed and popular compositions.
The above text from the Wikipedia article "Fantaisie-Impromptu" text is available under CC BY-SA 3.0.