ALGIERS — Two years ago, a motley collection of prisoners spent night after night repeating their telephone numbers to one another from within the dark and dirty cells where they were being held in Afghanistan. Anyone who got out, they said they agreed, would use the numbers to contact the families of the others to let them know that they were still alive. At least two of those men are now free and, thanks to the memorization exercise, are back in touch with each other. [...] In May 2003, Mr. Saidi was expelled from Tanzania, where he ran a branch...