World War One divided the socialist movement internationally: collaboration or resistance? Here is the resisters' story.
"War on War is the most comprehensive study to date on the great socialist struggle against war that began at the Zimmerwald Conference in 1915. Dismissed by contemporaries and all too many historians as a mere defeatist grouplet of the Second International, the Zimmerwald Left led by Lenin emerges in Nation's book as a noble if doomed tendency within European social democracy."-- Woodford McClellan