Simms, a Cambridge historian, attributes responsibility for the deadly breakup of Bosnia to the policies of the British government under Prime Minister John Major. The argument: A political class inclined toward appeasement, backed by a pro-Serb military and diplomatic establishment and a docile Parliament, failed to stand up to Serb aggression and left Bosnia to its fate. The polemic is impressively researched and powerfully argued but also one-sided. Croatia's brutal 1995 expulsion of some 150,000 Serbs from the Krajina region is mentioned late in the book but glossed over, and the depiction of newly created Bosnia as "an embattled member of the United Nations" is just too simple. The fact is that all the options faced by the United Kingdom and its allies were bad ones. Still, Simms is more right than wrong to criticize a government that allowed its legitimate concerns about getting dragged into a war to lead to a failure to deter Serb aggression, a deep crisis in the Atlantic alliance, a stain on the reputation of the UN, and the worst atrocities in Europe since World War II.