Pentagon Papers were given ("leaked") to the The New York Times

Pentagon Papers
From Wikipedia, the free encyclopedia.

The Pentagon Papers is the colloquial term for United States-Vietnam Relations, 1945-1967: A Study Prepared by the Department of Defense, a 47 volume, 7,000-page, top-secret United States Department of Defense history of the United States' political and military involvement in the Vietnam War from 1945 to 1971, with a focus on the internal planning and policy decisions within the U.S. Government. The study was commissioned in 1967 by Robert McNamara, the then-Secretary of Defense. The Papers included 4,000 pages of actual documents from the 1945-1967 period, and 3,000 pages of analysis.
Most, but not all of the Pentagon Papers were given ("leaked") to the The New York Times in early 1971 by Department of Defense employee Daniel Ellsberg.

Earlier: NYT NSA

Iraq: Learning the Lessons of Vietnam By Melvin R. Laird - From Foreign Affairs, November/December 2005
There were two things in my office that first day that gave my mission clarity. The first was a multivolume set of binders in my closet safe that contained a top-secret history of the creeping U.S. entry into the war that had occurred on the watch of my predecessor, Robert McNamara. The report didn't remain a secret for long: it was soon leaked to The New York Times, which nicknamed it "the Pentagon Papers."