While the formal classification system used to keep sensitive government information secret was a 20th Century development, even in the 19th Century, new research shows, the Department of State had to balance the "public's right to know" with protecting national interests. Foreign policy documents were often released soon after events took place, sometimes complicating diplomatic relations. In certain instances sensitive documents and information were withheld, usually in the name of national security, but occasionally for political advantage. Congress, the media, public audiences, and other governments all took an interest in this peculiarly American penchant for walking the tightrope between transparency of governmental operations and withholding information "not in the public interest."

Organized in cooperation with the State Department's Office of the Historian in connection with the sesquicentennial of the Foreign Relations of the United States series, Diplomatic Secrecy in the 19th Century will explore the earliest available examples of both America's open and secret diplomacy, as well as how the ad-hoc system used in the 19th Century formed the basis for the formalized system which was developed in later years.

Aaron Marrs earned his PhD at the University of South Carolina and for the past five years has been on the staff of the Office of the Historian at the U.S. Department of State. He is the author of Railroads in the Old South: Pursuing Progress in a Slave Society, published by Johns Hopkins University Press in 2009.

Peter Cozzens is Special Assistant to the Historian of the Department of State. As a longtime Foreign Service Officer, he has extensive experience in front-line diplomacy. Mr. Cozzens is also an award winning author of multiple books about the Civil War and post-Civil War American history.

William B. McAllister is Chief of the Special Projects Division at the State Department Office of the Historian and director of the FRUS Sesquicentennial Research Project. He earned his Ph.D. at the University of Virginia and is the author of Drug Diplomacy in the Twentieth Century and other works about international history in the 19th and 20th centuries.