Credibility and journalistic heroism, as each year’s prizes show, reside in the pages of prestige publications; the New York Times and the Washington Post are mainstays, and since the prizes were first opened up to include magazines in 2015, The New Yorker is as well. No truth is really a truth, particularly a courageous truth, until it appears in their pages. The brown man, the accused terrorist, the actual torture survivor Mohamedou Ould Salahi may have written a great book. But the definitive story about “Guantánamo’s Darkest Secret” is the one penned by Taub.