Piano Concerto for the Left Hand in D

I am listening to this Ravel's masterpiece. I am not very acquainted with Ravel, but I heard about this concert on the radio and I got a cd from a colleague. It's a very nice piece of music, and it sounds typically as Ravel. The story behind it is very nice. The concert has been written for pianist Paul Wittgenstein who lost his right arm in WWI. Wittgenstein was the brother of philosopher Ludwig Wittgenstein. What a nice gesture, to write a concerto just for one hand. Unfortunately it did not help preventing WWII.