It's one of the iconic photographs of American history: A Black teenager, a policeman and his lunging German Shepherd. Birmingham, Alabama, May of 1963. In May of 2020, as reporter Paul Kix stared at a different photo-that of a Minneapolis police officer suffocating George Floyd-he kept returning to the other photo taken half a century earlier, haunted by its echoes. What, Kix wondered, was the full legacy of the Birmingham photo? And of the campaign...