Tapping new sources for the first time, this must surely be considered the definitive work on Americans who fought and died for the Spanish Republic. Historian Carroll (It Seemed Like Nothing Happened, 1982, etc.) examines the trajectory of the 3,000 Americans who fought during the Spanish Civil War (193639). Though they were often called ``The Abraham Lincoln Brigade,'' this appellation, he notes, is not strictly correct. The first Americans to aid Republican Spain served in the Abraham Lincoln battalion of one of the International Brigades (composed of non-Spaniards), but this was only a fraction of all US volunteers. Still, the moniker gained currency to refer to all Americans who fought for the Republic. Carroll broadly traces the motivations of those who volunteered. Most, but not all, were Old Left Communists (the first detachment of Americans was recruited on the instructions of Moscow) who signed up to save a beleaguered socialist ally. Some felt that American democratic ideals were at stake as Fascists under Franco sought to overthrow the duly elected Socialist Popular Front. About one third of the volunteers were Jews, aware early on of the perils of Fascism. For all, Carroll says, the war became the most significant event of their lives. Carroll examines not only the battles (from the Americans' first appearance, when they were mistaken for Russians and saved Madrid from being overrun by Royalist Fascists) but also the soldiers' homecomings and their years as veterans. Many went on to aid US intelligence against the Fascists in the early days of WW II despite an order of neutrality from Russia. The story is brought down through their political activities of the McCarthy era and to the present day. With access to previously unattainable archives in Moscow and using extensive interviews and written material, Carroll tells a magnificent tale of hope, idealism, heroism, honor, death, and betrayal.