Polonaise-fantaisie in A-flat major, Op. 61, is a composition for piano by Frédéric Chopin. It was dedicated to Mme A. Veyret, written and published in 1846.

This work was slow to gain favour with musicians, due to its harmonic complexity and intricate form. Arthur Hedley was one of the first critics to speak positively of the work, writing in 1947 that it 'works on the hearer's imagination with a power of suggestion equaled only by the F minor Fantasy or the fourth Ballade', although Arthur Rubinstein, Leff Pouishnoff, Claudio Arrau and Vladimir Horowitz had been including it in their programs some decades earlier.

It is intimately indebted to the polonaise for its metre, much of its rhythm, and some of its melodic character, but the fantaisie is the operative formal paradigm, and Chopin is said to have referred initially to the piece only as a Fantasy. Parallels with the Fantaisie in F minor include the work's overall tonality, A-flat, the key of its slower middle section, B major, and the motive of the descending fourth.
Wiki article