Bortkiewicz is roughly contemperaneous with Rachmaninoff (1877-1952). He studied composition with Liadov, and was a very accomplished pianist. He moved around quite a bit, finally settling in Austria (if he had settled in the US like Rachmaninoff, undoubtedly, he'd be much more well known today). He composed a TON of piano music, sonatas, etudes, preludes, character pieces, and four concerti (one of which is for the left hand).
koji