All that can presently (May 2013) be gleaned about by internet searching is that William Hyder is the one-off composer of Polyphonic Rag (1979).
Surfers are welcome to contribute information about this composer.
Ragtime Music CDs:
CD(s) & MP3 Album(s)
This list is arranged in chronological order and contains 1 work by William Hyder.
It does not claim to be complete and represents only the number of items located.