Much of a nation's foreign policy goes on behind the scenes, but it is those deliberations that are key to understanding decision making. In the 1970s, the Federal Government instituted a process under which documents that went into the formation of our foreign policy could be made public. The Boston Public Library for received a microfiche collection of Declassified Documents that was the main way to access such materials. It is an annoying collection, as each year's items did not correspond to a particular time period, only being a representation of when the materials were made available for public viewing during said year. George Washington University has made an archive of declassified materials online, too, as has the Federation of American Scientists.
The State Department does have an online reading room of materials that have been made public through Freedom of information Act requests. The same is true of the Central Intelligence Agency and the National Security Council. The Boston Public Library also has a microfilm collection of NSC documents.
Image on right- Don Ferguson, artist. Date every classified document, Oct. 22 1964. Artist Poster Collection. Library of Congress Prints & Photographs Division.