Kerry will likely be remembered as the last U.S. secretary of state whose outlook reflected the assumptions and aspirations of the post Cold War unipolar era in world politics. For Kerry, the job involved serving as a kind of global first responder. Christmas 2013 found him managing a crisis in South Sudan: “I was talking to our embassy in Juba and the White House as we tracked militias and fighters. . . . If they reached Juba, and the fighting devolved into chaos, it would be ‘Katy, bar the door!’” Kerry’s successors are unlikely to follow the news in Juba as closely. In other ways, too, Kerry, a son of the old wasp ascendancy, seems to belong to an America that is rapidly receding in the rearview mirror. Kerry saw U.S. power much as he saw his own privilege: as a call to service. His memoir gives a comprehensive and, in places, moving account of his response to that call. People disagree over the wisdom and effectiveness of U.S. foreign policy in the Kerry years, but there can be no serious dispute about the integrity and patriotism that Kerry brought to the job.