1. Investigation on the Theory of the Photographic Process
by Sheppard SE. With CE. Kenneth Mees. S. E. C. E. 
Price: USD 36.75
Dealer: Biblio, Burton Lysecki Books, ABAC/ILAB
Description: London: Focal Press [0-240-50694-4] 1969. (4to) 342pp. Near fine in very good plus dust jacket. Facsimile reprint of the 1907 edition. Illustrations, photographs, tables, charts, index. (Photography, Photography--Theory, Science--Photography). Focal Press ISBN 0240506944 9780240506944 [CA] 

2. Investigation on the Theory of the Photographic Process
by Sheppard, S.E. (With C.E. Kenneth Mees.) 
Price: USD 36.75
Dealer: Abebooks, Burton Lysecki Books, ABAC/ILAB
Description: ISBN10: 0240506944, ISBN13: 9780240506944, [publisher: Focal Press, London] Hardcover [0-240-50694-4] 1969. (4to) Near fine in very good plus dust jacket. 342pp. Facsimile reprint of the 1907 edition. Illustrations, photographs, tables, charts, index. (Photography, Photography--Theory, Science--Photography) [Winnipeg, MB, Canada]