Prokofiev's Piano Concerto No. 4 in B-flat major for the left hand, Op. 53, was commissioned by the one-armed pianist Paul Wittgenstein and completed in 1931. The concerto has four movements, lasting around 24 minutes.
Wittgenstein did not understand the work, but it is not the case (as has sometimes been claimed) that he refused to play it. He was simply not prepared to play it until such time as he had appreciated its inner logic. That time never came, but Wittgenstein and Prokofiev always remained on friendly terms.