What would you do if you carried a Big Secret, a real whopper that would shake an institution to its foundations, public or private? Whistleblowing is tricky business. It’s protected under law when exposing wrongdoings by private corporations, but protections are not necessarily practical; big business pays big lawyers. And look out if you have dirt on the government. Regardless of how big the malfeasance or the lie, they will come for you, no matter who’s sitting in the Oval Office.

Obviously current events come to mind, and this month Steven Spielberg’s The Post—starring Meryl Streep as Washington Post publisher Katharine “Kay” Graham and Tom Hanks as executive editor Ben Bradlee—opens across the country. The film recreates the mad rush to be the first to publish the Pentagon Papers, the set of classified documents leaked by Daniel Ellsberg that outlined the realities of the Vietnam War, the scale and illegality of which was unknown to the American public. Ellsberg risked personal catastrophe in disclosing classified documents, but to him, the benefit to the country—and his duty—outweighed the possibility of a lengthy prison sentence. Give Hanks credit for courage, as well: following Jason Robards’s perfect turn as Bradlee in All the President’s Men, even more than 40 years later, takes guts. (Full and probably unnecessary disclosure: Amazon.com founder and CEO Jeff Bezos also owns the Washington Post.)

So, in the spirit of the season, here’s a list of truth-tellers, sneaks, spies, and tattletales (depending on you point of view) and books by or about them.

Daniel Ellsberg 

Ellsberg was a bigger double-dipper than even George Costanza. While he was busy photocopying the Pentagon Papers, he was also collecting information about the capabilities of the United States’ nuclear arsenal, especially its philosophies and strategies regarding its use. Again, what he found was not what we’d been told—that these devastating weapons only existed as a method of deterrence, a looming threat against anyone considering acting against us. Rather, the options of “first strike” or “first use” were, and are, always key components of American foreign strategy. He lost those copies long ago, and for decades he held his knowledge close for fear of (more) prosecution. But more recent Freedom of Information Act disclosures have made him a little more comfortable in sharing his experience and information, now collected in The Doomsday Machine. It’s not reassuring.

Mark Felt 

“Follow the money.” For more than 30 years, the identity of Deep Throat, the informant who helped Bob Woodward and Carl Berstein bring down Nixon’s White House, remained the greatest pseudo-mystery of the Watergate scandal. I say “pseudo” because many (including Nixon, himself) suspected it was Felt all along. This was a big deal: at the time, he was the FBI’s Associate Director, i.e. second in command of the federal government’s primary law enforcement agency. But Felt’s conviction—born of deep patriotism—that a “Lone Ranger” was required to expose the criminal cover-up at the highest levels of government overrode what must have been deep misgivings. An unfortunate footnote: Felt reportedly never spoke that famous line from the film adaptation of All the President’s Men, at least to Woodward.

Karen Silkwood

Felt’s concerns were well founded, because blowing whistles doesn’t always work out for those who blow them. Take the case of Silkwood, a technician for the chemical company Kerr-McGee. A union activist, Silkwood had collected information concerning worker safety at the nuclear fuel manufacturing facility where she worked. She claimed that faulty manufacturing of fuel rods put employees under the risk of radioactive contamination, and Silkwood had discovered herself that she been exposed to 400 times the maximum “safe” level of plutonium, whatever that means. Kerr-McGee countered that she had contaminated herself. On November 13, 1974, Silkwood was on  her way to meet with a New York Times reporter when her car left the highway and crashed into a culvert, killing her. Though ruled an accident by police, others have maintained that mysterious circumstances—missing documents, unexplained damage to her car—point toward assassination. You decide.

Herbert Yardley

Sometimes the motivation for spilling secrets is a bit more personal. Yardley was a pioneer of cryptanalysis for the United States, the founder of the somewhat-under-the-radar American Black Chamber organization tasked with breaking diplomatic codes. When President Herbert Hoover and Secretary of State Henry Stimson learned of Yardley’s activities, Stimson, in a statement unthinkable now, declared “Gentlemen do not read each other’s mail” and put Yardley out of a job. Needing an income source other than poker, he wrote a tell-all that immediately became a bestseller, one that today would have landed him in prison for a very long time. Or at least exile.

Linda Tripp

Other times, motivations are murkier. Why did Tripp befriend White House intern Monica Lewinsky, then secretly record their conversations about the latter’s illicit relationship with President Clinton? If it was out of a sense of patriotism, it’s a little strange that she did it after taking the advice of a conservative literary agent. (Two comments here: 1. A “conservative literary agent” must be some sort of rara avis. 2.) Take your legal advice from a lawyer.) Then she gave the tapes to Kenneth Starr in exchange for immunity from… recording them? There’s more of it, and it’s all beyond sketchy. But stuff was definitely going on; what you make of it probably aligns with your political preferences. What a mess.

Edward Snowden

Edward Snowden is a former CIA employee and NSA contractor who left work one day with a thumb drive packed with documents describing the U.S. government’s programs for mass surveillance. Edward Snowden is a traitor who tipped off our enemies to valuable tools used to combat terrorism, undermining the security and safety of our country and its citizens. Edward Snowden is a hero for exposing spy agencies run amok, operating outside the law and amassing data on Americans without warrants. Edward Snowden is a Russian stooge. Edward Snowden is trapped in Russia, unable to leave after his passport was revoked by the Obama administration. Edward Snowden is brave. Edward Snowden is a rat.