David,

Directory publishing, especially back in the day, worked on an annual cycle.
In a large phone company such as New York Telephone, each directory had a
different publication date, in order to load-balance the clerical and
typographical work over the year (esp. before computers). >from the
publication date, back up several weeks to the "directory close" date, when
the set of directory listings to be published was frozen (i.e. after which
new and changed customers were not added and disconnecting customers were
not deleted). After the close, with rare exceptions for business listings,
only proofreading editing was generally done.

The physically binding of the directory generally had printed on it a month
in which the directory was actually published. So if the Manhattan directory
says "July 1949," figure it closed about April or May. And remember that
each borough had its own directory - there was no "New York City phone directory".

Steve Stein
Highland Park, NJ
(who for many years worked in White Pages publishing)