Encyclopedia of Type Faces, W.P. Jaspert et al.
American Metal Type Faces of the 20th Century, M. McGrew

Thanks. I'm assuming these titles could possibly be found at a library? Or are we talking rare...

I think we are talking 'rare' if it is like :
Pelletteri, Giuseppe. 1963, Atlante Tipologico ; SEI, Torino.
http://www.nopress.it/aldrovandi/articolo.php?art=57
the same specimen book quoted at :
http://cgm.cs.mcgill.ca/~luc/nonsolusstory.html -
http://www.typophile.com/forums/messages/30/42604.jpg

Best,
AS

They are in print: American Metal Typefaces and Encyclopedia of Typefaces

Great, that'll probably work. Thanks a bunch.