The earliest surviving version of the popular Valse-Impromptu was written by Liszt into the diary of Tsaritsa Aleksandra Feodorovna on his visit to St Petersburg in 1842. This version appeared in print the following year as Petit valse favorite. On his next visit to Russia, in 1843, Liszt wrote a musically and technically more demanding version for Countess Marie Kalergis, a pupil of Chopin, but this was never published in the composer's lifetime. A final version, similar in shaping to the second, appeared in 1853 with the title Valse-Impromptu. The present edition contains the score of all three versions as published in the New Liszt Edition, with the critical notes to them and prefaces in English and German covering all the main issues of the work's origin and interpretation.