Once a classical instrumentalist has injured or lost a hand or arm, there's often little that can be done to reclaim his performance career. But the Austrian pianist Paul Wittgenstein found a world-changing workaround when a combat injury in World War I caused him to have his right arm amputated, at a time when Wittgenstein's career as a professional pianist was just getting started. It was a devastating injury but one that Wittgenstein was determined not to let sideline him. Still, in addition to the obvious problem of how to play the piano to the instrument's full expressive force with only one hand, Wittgenstein was confronted with the challenge of finding concert-worthy piano repertory for left hand alone. Simply put, there wasn't any. So he made some happen by commissioning composers and by arranging two-hand piano works for left hand alone. The list of twentieth-century composers who contributed left-hand piano concertos reads like a Who's Who of modern music and includes Maurice Ravel, whose Piano Concerto for the Left Hand is the most famous work in this repertoire. Watch this video of Paul Wittgenstein playing Ravel's Piano Concerto for the Left Hand and revel in astonishment at the human spirit.