black keys only, please

Here is an extract from the entry for Irving Berlin in Benet's Reader's Encylopedia:

Berlin had an extrodinary range of musical styles and was one of the few in the American music business (Cole Porter was another) who could successfully write both words and music. His accomplishments were all the more impressive in light of the fact that he had no musical training; he played only the black keys on his piano and only in the key of F sharp. He had a mechanism built into his piano that would change keys for him.

That last point is important becuase so much of the repitoire from that time comes from him and it would have been pretty boring if it all was in F sharp. Of course it would also have made things a little easier for other musician who normally play in a variety of keys only to have to worry about the one key (similar in principle to the blues progression: you know what's expected and are happy to deliver).