“I guess I could use some of this time to get into pleasantries,” Belafonte begins, “to talk about the many experiences I’ve had with you not only here but in Europe and other places.” This, it’s clear as he pauses to raise his head, isn’t what he wants to do. “What do you have in store for us this summer?” Now King joins in the crowd’s nervy laughter: the summer of 1968, everyone seems to sense, is going to be a doozy. And America’s foremost activist for justice is glad to explain, by way of a capsule history of the past few years in American life, what he’s focusing on now. King says that the passage of the Civil Rights and Voting Rights Acts were great victories. But they’ve done little, in the three years since the latter’s passage, to undo inequalities built over centuries. And redressing such ills will require more than confronting prejudice. “I feel,” he intones, “that we are in the midst of a most critical period in our nation. And the …