A fascinating, but challenging, area to collect is the Departmental Stamps of Argentina. The challenge is not the cost as few of them beyond the pocketbook of most collectors but the ability to find them.
The stamps were issued between 1913 and 1937 and so appear on the regular issues of 1911 to 1937. The following departments are known:
M.A. (Ministry of Agriculture)
M.G. (Ministry of War)
M.H. (Ministry of Finance)
M.I. (Ministry of Interior)
M.J.I. (Ministry of Justice and Instruction)
M.M. (Ministry of Marine)
M.O.P. (Ministry of Public Works
M.R.C. (Ministry of Foreign Affairs and Religion)
As far as I know, the best catalog for this issues is the 1958 Kneitchel catalog of Argentina. This two-volume work, unfortunately, is not easily found today. From time to time it is offered in auctions of philatelic literature, however.
These stamps offer the philatelist the opportunity for many hours of pleasure because of the various paper types, perforations, watermarks, methods of printing the basic stamps and varieties.
The following pictures show some of the things that can be found: