“He was the most successful and valued agent the United States had run inside the Soviet Union in two decades. His documents and drawings had unlocked the secrets of Soviet radars and weapons research years into the future. He had smuggled circuit boards and blueprints out of his military laboratory. His espionage put the United States in position to dominate the skies in aerial combat and confirmed the vulnerability of Soviet air defenses — showing that American cruise missiles and strategic bombers could fly under the radar.”
Source: How the CIA ran a ‘billion dollar spy’ in Moscow – Military history – Stripes
