As part of a crackdown against critics, Egypt's military-backed government has been jailing journalists and activists. But the government hasn't entirely silenced them.
Writing surreptitiously and risking additional punishment, several of those detained have managed to write letters that have been smuggled out of prison or released by the authorities.
"I am nervous as I write this," detained Al Jazeera English correspondent Peter Greste said in a letter published by his network.
Greste, an Australian who was detained in a Dec. 29 raid on his hotel, said he's afraid that his writing could prompt prison authorities to take away his "tiny joys" — a reference to the several books he has and the occasional time he's allowed to spend outdoors.
Greste decided to write because he thought that keeping silent would validate the jailing of him and his colleagues as well as "freedom of speech across Egypt."
"The prisons are overflowing with anyone who opposes or challenges the government," he wrote.
The public prosecutor has charged Greste with colluding with a terrorist organization. His Egyptian colleagues Mohammed Fadel Fahmy and Baher Mohamed stand accused of belonging to a terrorist group.
The charges stem from alleged contact they've had with the Muslim Brotherhood, the Islamist group that dominated Egypt's elections and was running the country before being ousted by the military last July. The organization has now been declared a terrorist group.
Alaa Abdel Fattah, a prominent blogger and activist, has been detained on charges relating to Egypt's controversial new protest law, which outlaws demonstrations that haven't been approved in advance by authorities.
In a letter to his sisters published on the Egyptian news website Mada Masr, Abdel Fattah describes the arbitrary quality of prison life.
"The feeling that the authorities can just bureaucratically decide when to open my door or when I will find a piece of carton to block my window or when the warden will get permission to locate a ladder and block the windows [to stop the cold] is oppressive," he writes.
Abdel Fattah is no stranger to Egyptian prisons — he was detained in 2006 under the former president, Hosni Mubarak, and again under Egypt's ruling generals in 2011.
Despite his previous time behind bars, it's not any easier now.
"Every time I am jailed, a piece of me breaks," he writes.
He says the only upside to his detention is that it frees him "from the guilt I would feel being unable to combat the immense oppression and injustice that is ongoing."
Prison authorities eventually handed over Alaa's letter to his family, though his sister Mona Seif wrote on her blog that it took weeks to persuade them.
Other detainees, like Ahmed Maher, say that writing is extremely risky. Maher, a co-founder of the April 6 youth movement, received a 3-year sentence on charges of breaking the new protest law.
In prison letters published on his blog, he writes that "whoever is caught with a pen or paper is tortured along with all those with him."
He writes covertly with the tip of an old pen, in a cell so cold that it keeps his food from spoiling. He says he doesn't even feel cold anymore.
"I don't feel anything at all," he writes.
Many of the inmates filling Egypt's prison cells, and there are thousands, are supporters of the ousted president, Mohammed Morsi, and his organization, the Muslim Brotherhood.
The government routinely rounds up supporters of Morsi and the Muslim Brotherhood at near-daily protests.
Mohamed Soltan is an Egyptian-American who volunteered to work on President Obama's 2008 presidential campaign in Ohio, where Soltan was a student at Ohio State University at the time.
Soltan was shot in the arm during a protest and was recovering at his home in Cairo when he was arrested in August. From prison, he penned an open letter to Obama that was recently published on the New York Times website.
He says his cellmate recently performed makeshift surgery on his wounded arm.
"He used pliers and a straight razor in lieu of a scalpel," Soltan writes, adding that he was on a dirty mat without any anesthesia.
He says he feels abandoned by the U.S. president and the American government, which has "left a sting in me that is almost as intense as the sharp pain emanating from my recently sliced arm."