In THE AMBASSADORS, we meet Ryan Crocker, a six-time ambassador who twice ran the embattled U.S. embassy in Afghanistan and served as ambassador to Iraq at the peak of the successful U.S.-Iraqi effort to calm a bloody civil war. Then there’s Robert Ford, who was taken hostage by a Shia militia during his long service in Iraq, and later, as ambassador to Syria, stood up to a dictator who was slaughtering his own people. Anne Patterson, who proved her negotiation skills in Colombian drug wars, brokered behind-the-scenes political deals in Islamabad to help prevent the collapse of a shaky government. And there’s Christopher Stevens, a charismatic foreign service talent who stole into Libya under a rain of bombs to guide American leaders though a civil war, and was ultimately killed in the 2012 terrorist attack in Benghazi.