W.M. Hickman 
Last updated: 22.06.17
All that can presently (November 2015) be gleaned about by internet searching is that W.M. Hickman is the one-off composer of Diplomat Rag (1913) published by William H. Hickman, Covington, Kentucky, USA.
Surfers are welcome to contribute information about this composer.

Further sheet music at DBE: ON HOLD