Humanities › History & Culture History of Russian Espionage Russia's Most Notorious Attempts to Spy On the West Share Flipboard Email Print History & Culture American History Basics Important Historical Figures Key Events U.S. Presidents Native American History American Revolution America Moves Westward The Gilded Age Crimes & Disasters The Most Important Inventions of the Industrial Revolution African American History African History Ancient History and Culture Asian History European History Genealogy Inventions Latin American History Medieval & Renaissance History Military History The 20th Century Women's History View More By Robert McNamara History Expert Robert J. McNamara is a history expert and former magazine journalist. He was Amazon.com's first-ever history editor and has bylines in New York, the Chicago Tribune, and other national outlets. our editorial process Robert McNamara Updated October 02, 2017 Russian spies have been actively collecting material about the United States and its allies from the 1930s right up until the email hacking in the 2016 presidential election. Here is a look at some of the most notable Russian espionage cases, beginning with the "Cambridge Spy Ring" formed in the 1930s, who were motivated by ideology, to more mercenary American moles who fed information to the Russians in recent decades. Kim Philby and the Cambridge Spy Ring Harold "Kim" Philby meeting the press. Getty Images Harold "Kim" Philby was perhaps the classic Cold War mole. Recruited by Soviet intelligence while a student at Cambridge University in the 1930s, Philby went on to spy for the Russians for decades. After working as a journalist in the late 1930s, Philby used his lofty family connections to enter MI6, Britain's secret intelligence service, at the beginning of World War II. While spying on the Nazis, Philby also fed intelligence to the Soviets. After the end of the war, Philby continued spying for the Soviet Union, tipping them off about the deepest secrets of MI6. And, thanks to his close friendship with American spymaster James Angleton of the Central Intelligence Agency, it is believed Philby also fed the Soviets very deep secrets about American intelligence in the late 1940s. Philby's career was ended in 1951, when two close associates defected to the Soviet Union, and he came under suspicion as "The Third Man." In a celebrated press conference in 1955 he lied and quelled the rumors. And, astoundingly, he actually rejoined MI6 as an active Soviet agent until he finally fled to the Soviet Union in 1963. The Rosenberg Spy Case Ethel and Julius Rosenberg in a police van following their espionage trial. Getty Images A married couple from New York City, Ethel and Julius Rosenberg, were accused of spying for the Soviet Union and put on trial in 1951. Federal prosecutors claimed the Rosenbergs had given secrets of the atomic bomb to the Soviets. That appeared to be a stretch, as it was unlikely the material Julius Rosenberg obtained could have been very useful. But with the testimony of a co-conspirator, Ethel Rosenberg's brother David Greenglass, the two were convicted. Amid enormous controversy, the Rosenbergs were executed in the electric chair in 1953. The debate about their guilt continued for decades. After the release of material from the former Soviet Union in the 1990s, it appeared that Julius Rosenberg had indeed been providing material to the Russians during World War II. Questions about the guilt or innocence of Ethel Rosenberg still remain. Alger Hiss and the Pumpkin Papers Congressman Richard Nixon inspecting Pumpkin Papers microfilm. Getty Images A spy case which hinged on microfilms stashed in a hollowed out pumpkin on a Maryland farm captivated the Ameircan public in the late 1940s. In a front-page story on December 4, 1948, the New York Times reported that the House Un-American Activities Committee claimed it had "definite proof of one of the most extensive espionage rings in the history of the United States." The sensational revelations were rooted in a battle between two old friends, Whittaker Chambers and Alger Hiss. Chambers, an editor at Time magazine and a former communist, had testified that Hiss had been also been a communist in the 1930s. Hiss, who had occupied high foreign policy positions in the federal government denied the charge. And when he filed a lawsuit, Chambers responded by making a more explosive charge: he claimed Hiss had been a Soviet spy. Chambers produced reels of microfilm, which he had hidden in a pumpkin on his Maryland farm, that he said Hiss had given him in 1938. The microfilms were said to contain U.S. government secrets that HIss had passed to his Soviet handlers. The "Pumpkin Papers," as they became known, propelled the career of a young congressman from California, Richard M. Nixon. As a member of the House Un-American Activities Committee, Nixon led the public campaign against Alger Hiss. The federal government charged Hiss with perjury, as it was unable to make a case for espionage. At a trial the jury deadlocked, and Hiss was retried. At his second trial he was convicted, and he served several years in federal prison for the perjury conviction. For decades the issue of whether Alger Hiss had really been a Soviet spy was hotly debated. Material released in the 1990s seemed to indicate that he had been passing material to the Soviet Union. Col. Rudolf Abel Soviet spy Rudolf Abel leaving court with federal agents. Getty Images The arrest and conviction of a KGB officer, Col. Rudolf Abel, was a sensational news story in the late 1950s. Abel had been living in Brooklyn for years, operating a small photography studio. His neighbors thought he was an ordinary immigrant making his way in America. According to the FBI, Abel was not only a Russian spy, but a potential saboteur ready to strike in the event of war. In his apartment, the feds said at his trial, was a shortwave radio by which he could communicate with Moscow. Abel's arrest became a classic Cold War spy story: he mistakenly paid for a newspaper with a nickel that had been hollowed out to contain microfilm. A 14-year-old newsboy turned the nickel over to the police, and that led to Abel being put under surveillance. The conviction of Abel in October 1957 was front-page news. He could have received the death penalty, but some intelligence officials argued that he should be kept in custody to trade if an American spy was ever captured by Moscow. Abel was eventually traded for American U2 pilot Francis Gary Powers in February 1962. Aldrich Ames The arrest of Aldrich Ames. Getty Images The arrest of Aldrich Ames, a veteran of the C.I.A. for 30 years, on charges of spying for Russia sent a shock through the American intelligence community in 1994. Ames had given the Soviets the names of agents working for America, dooming the operatives to torture and execution. Unlike earlier notorious moles, he was doing it not for ideology but money. The Russians paid him more than $4 million over a decade. Russian money had lured other Americans over the years. Examples included the Walker family, which sold U.S. Navy secrets, and Christopher Boyce, a defense contractor who sold secrets. The Ames case was particularly shocking as Ames had been working in the CIA, both in the Langley, Virginia, headquarters and at postings overseas. A somewhat similar case became public in 2001 with the arrest of Robert Hanssen, who had worked for decades as an FBI agent. Hanssen's specialty was counterintelligence, but instead of catching Russian spies, he was secretly being paid for work for them.