Once I launched Solitary Watch, I learned of a handful of other reporters who were encountering the same restrictions—and working around them and in spite of them. “I was never able to get inside” a SHU in New York, Mary Beth Pfeiffer, a reporter for the Poughkeepsie Journal, wrote in an email. “In 2001, after I began writing about links between solitary confinement, mental illness, and suicide, they refused even to let me into any of their prisons except through the visiting room. Even there, I once had my notes seized by prison officials who claimed note-taking was not permitted.” Pfeiffer says she relied on “official reports of conditions and suicides there, and the accounts of former prisoners.”

George Pawlaczyk and Beth Hundsdorfer of the Belleville News-Democrat authored a series of articles called “Trapped in Tamms,” about the supermax prison in southern Illinois. The 2009 series, which won a George Polk award, revealed horrendous treatment of mentally ill prisoners and the cruel attitudes of the prison officials, including doctors. Unable to secure a visit, Pawlaczyk says their reporting was based largely on court documents, mostly depositions, and the surprise finding that one Illinois county’s mental health reports were filed and open to the public.

Susan Greene, the former Denver Post reporter who in 2012 wrote “The Gray Box,” a blistering report focusing on ADX, for the Dart Society, says she couldn’t even get close to the prison, which has been completely off-limits to the press since 9/11. “I have had absolutely no access to the place at all,” she told me. When she pulled up in front of the driveway to the remote prison complex, she was chased away by armed guards. But in addition to public records, Greene based her reporting on correspondence with prisoners in extreme isolation, carried on over more than a year. Ironically, once her article was published, she could not send it to her correspondents in ADX, due to a policy against allowing prisoners’ names in an article. “So I redacted all the prisoners’ names,” she said, “and then it came back saying something like, ‘You can still see it if you hold it up to the light.’ Out of frustration and wanting to be a pain in the ass, I Exacto-knifed out all the names and sent it, and it still didn’t get through.”

Shane Bauer, who wrote a 2012 expose about solitary confinement in California for Mother Jones, also relied heavily on correspondence with dozens of prisoners in Pelican Bay and other state SHUs who had staged several highly publicized hunger strikes after years or decades in isolation. Bauer spent more than two years in an Iranian prison after being captured on the Iran-Iraq border, including four months in isolation, and thus has the rare perspective of someone who has himself experienced solitary. He also succeeded in gaining access to Pelican Bay, though it was severely limited and carefully orchestrated. Bauer says he was taken to a unit full of men who had cooperated with prison officials by passing on information about prison gangs, “and was allowed to interview one inmate while the gang investigator stood by.” Visits to the solitary cells were refused, as were interviews by the warden and top corrections officials.

Lance Tapley began writing about solitary confinement for the Portland Phoenix seven years ago, when a supermax prisoner named Deane Brown got in touch with him. Brown “wanted to expose to the outside world the torture he was experiencing and seeing in the Maine State Prison’s Special Management Unit,” Tapley wrote to me. Initially denied access to SMU prisoners, Tapley was able to convince the governor’s office to intervene. Then he was allowed to interview several men “in hand and foot shackles on the other side of a Plexiglas window.” Those six interviews and a leaked official videotape of a cell extraction, plus interviews with the corrections commissioner, defense attorneys, and others, formed the basis of his first supermax stories. Once those stories were published, Tapley was banned from the prison. And like many prisoners who talk to the press, Deane Brown faced retaliation: He was shipped to a prison out of state.

Where journalists have succeeded, one way or another, in penetrating the black sites, their reporting has undeniably had an impact. In Maine, it helped spark a grassroots movement and a legislative initiative, which eventually spurred the prison system to reduce its use of solitary confinement. In New York, it became ammunition in a battle to keep mentally ill prisoners out of solitary. And in Illinois, it provided fuel for an effort that has convinced the governor to shut down Tamms supermax prison.

James Ridgeway has been a reporter for close to 50 years, writing for The Village Voice, The New Republic, and Mother Jones, among others, and is the author of 16 books. He is co-editor, with Jean Casella, of the website Solitary Watch and a 2012 Soros Justice Media Fellow