In a message dated 1/31/2005 11:19:05 AM Eastern Standard Time, [log in to unmask] writes:
Primary Source Media had a marvelous collection of city directories on line. It was possible to search across time periods and localities in one search.....As I recall, Google has a cache of the homepage still available.
Yes, Leslie, I subscribed to the PSI Media directories and have written about them and their de-posting - as you have.  But a respondent to the question about a 1946 recording studio was "sure" there were mid-20th century directories posted on the web.  
 
My tally of the PSI directories does not tally 20th century  directories (and certainly nothing relevant to 1946) and my cache of the page defaults to their "no results" page:  "The web site you are trying to access was discontinued as of December 31st, 2001." 
 
Thus my own query: "If this or any subscriber is familiar with any 20th century city directories posted on-line, now or at any time in the past, I would be interested to hear  from them."     
 
Best,  Christopher