Marco's Comments:
Interesting book that examines current Erdnase candidates to see whom, if any, could be the author of "Expert at the card table". McDermott relies heavily on the Genii Forum's thread, and also on comparison of the text with known texts from the candidates.
According to the author, Erdnase may be either Milton Franklin Andrews (which I also believe may be) or Edwin Sumner Andrews, as championed by Richard Hatch.