There are three authors named William Ryan: a sociologist/social activist, am oceanographer, and an architectural historian.
According to Library of Congress on 3 July 2007:
Ryan, William, 1914- wrote White House.
Ryan, William, 1923- wrote Blaming the victim; Equality.
Ryan, William B. F. wrote Noah's flood.
This notice writer thinks The House on Willow Street was written by a further William Ryan.
There is a fourth William Ryan who is an Irish writer living in London whose debut novel, The Holy Thief has just been published