At the age of 83, when most oldies are tucking into their second cup of pudding, Don McCullin was flying in a Black Hawk helicopter after photographing land-mine victims in Yemen. He is now 90. His camera is his conscience and his conscience has no retirement plan. The greatest photojournalist of his or anyone’s generation, McCullin has documented the horrors and traumas of war (Vietnam), mass starvation (Biafra), sectarian violence (Northern Ireland during the Troubles), and mad tyranny (Idi Amin’s Uganda). His images are dark-toned, scarred with action and distress, filled with rubble, the haunting record of a world intent on ripping itself apart. It’s taken its toll on McCullin too. “I’ve got more tattoos on me, psychologically, than David Beckham,” he has said. But still he presses on, a lesson and a reprimand to us all. This comprehensive exhibition brings together nearly 50 works, as well as seldom seen archival materials and historical ephemera. —James Wolcott