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Ellsberg was A U.S. military analyst who, while employed by the RAND Corporation in 1971, released the Pentagon Papers, a top-secret Pentagon study of U.S. government decision-making in relation to the Vietnam War, to The New York Times.
W. Mark Felt
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A 2005 Vanity Fair article exposed Felt, a former FBI official, as "Deep Throat": The long-anonymous source who leaked secrets about President Nixon's Watergate cover-up to The Washington Post in the early 1970's.
Ultimately, Felt's devastating leaks as The Washington Post's secret Watergate source helped undermine Nixon's presidency.
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Pfc. Bradley Manning went on trial this month over the biggest leak of classified material in American history. Manning admitted turning over hundreds of thousands of documents to the anti-secrecy website WikiLeaks, pleading guilty earlier this year to charges that could bring 20 years behind bars. But the military pressed ahead with a court-martial on more serious charges, including aiding the enemy, which carries a potential life sentence.
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Sherron Watkins, an Enron Corporation Vice-President, exposed one of the largest accounting frauds in history, leading to a 24-year prison sentence for CEO Jeff Skilling.
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The former New York City police detective helped expose widespread corruption and bribery within the NYPD in the early 1970s.
Coleen Rowley
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A Minneapolis-based FBI agent, Rowley accused FBI headquarters of hindering efforts to investigate a suspected terrorist before September 11.
Linda Tripp
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While working at the Pentagon's public affairs office, Linda Tripp befriended Monica Lewinsky and later, secretly recorded their phone conversations. The tapes became a centerpiece of the investigation that exposed Lewinsky's affair with then-President Bill Clinton.
Dr. Jeffrey S. Wigand
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Formerly a research scientist for Brown & Williamson, Wigand was the first major tobacco insider to reveal that cigarette companies were consciously trying to get us hooked on nicotine, despite tobacco executives' public statements to the contrary. A two-part "60 Minutes" story that aired in 1996 inspired a Hollywood film, "The Insider," starring Russell Crowe.
