Quoting Christopher Simpson’s Blowback, chapter five:

Gehlen’s impact on the course of the cold war was subtle, but real. Self‐avowed pragmatists in the U.S. intelligence services have consistently argued that the otherwise questionable employment of Gehlen and even of unrepentant Nazis through the Org was justified by their significant contributions to fighting a powerful and ruthless rival: the Soviet Union. “He’s on our side,” CIA Director Allen Dulles later said of Gehlen, “and that’s all that matters.”

During the first decade following the war the United States spent at least $200 million and employed about 4,000 people full‐time to resurrect Gehlen’s organization from the wreckage of the war, according to generally accepted estimates. The Org became the most important eyes and ears for U.S. intelligence inside the closed societies of the Soviet bloc. “In 1946 [U.S.] intelligence files on the Soviet Union were virtually empty,” says Harry Rositzke, the CIA’s former chief of espionage inside the Soviet Union. “Even the most elementary facts were unavailable—on roads and bridges, on the location and production of factories, on city plans and airfields.” Rositzke worked closely with Gehlen during the formative years of the CIA and credits Gehlen’s organization with playing a “primary role” in filling the empty file folders during that period.

Intelligence gathered by the Org was “essential to American interests,” asserts W. Park Armstrong, the longtime head of the Office of Intelligence and Research at the Department of State. “Our German ally’s contribution to knowledge of the Soviet military was at times a standard against which we measured our own efforts.”

During the first years of the CIA under Rear Admiral Roscoe H. Hillenkoetter’s administration, according to a retired executive of the CIA’s Office of National Estimates, Gehlen’s reports and analyses were sometimes simply retyped onto CIA stationery and presented to President Truman without further comment in the agency’s morning intelligence summaries. Gehlen’s organization “shaped what we knew about the Soviets in Eastern Europe and particularly about East Germany,” he continued. Heinz Höhne, an internationally recognized historian and senior editor at Der Spiegel magazine, asserts that “seventy percent of all the U.S. government’s information on Soviet forces and armaments came from the Gehlen organization” during the early cold war. While any such precise number is bound to be arbitrary, the thrust of Höhne’s comment is certainly accurate.

(Emphasis added.)