A search for George Holton drew a blank on whowhere.lycos.com. An AltaVista search returned only two URL's, whose webmasters were contacted.

The first answered:

From: WRPRC Reference Desk <refdesk@primate.wisc.edu>

Unfortunately, our George Holton photo came from the collection of Harry Harlow, so we have no address available for the photographer.

Ray Hamel
refdesk@primate.wisc.edu
Wisconsin Regional Primate Research Center (608) 263-8316
University of Wisconsin - Madison
For AskPrimate
Primate Info Net -- http://www.primate.wisc.edu/pin/

And the second:

From: "Info@Mamiya" <danc@mamiya.com>

Thank you for your email inquiry.
Sorry, we do not have contacts with any one by the name of Thomas Holton or George Holton.

Regards,
Chris Mynio
Mamiya America Corp
8 Westchester Plaza
Elmsford, NY 10523
(914)347-3300
info@mamiya.com

Further searches led nowhere, and the publishers of Englert's book, Scribner's Sons, New York, were not found in the New York Yellow Pages.