Why do so many women organize against militarism and war? And why do they often choose to do so in women-only groups? This original study, the product of 80,000 miles of travel by the author over a two-year period, examines women's activism against wars as far apart as Sierra Leone, Colombia and India. It shows women on different sides of conflicts in the former Yugoslavia and Israel refusing enmity and co-operating for peace. It describes international networks of women opposing US and Western European militarism and the so-called 'war on terror'. Women are often motivated by adverse experiences in male-led anti-war movements, preferring to choose different methods of protest and remain in control of their own actions. But like the mainstream movements, women's groups differ - some are pacifist, others put justice before non-violence; some condemn nationalism as a cause of war, others see it as a legitimate source of identity. The very existence of feminist anti-militarism proposes a radical shift in our understanding of war, linking the violence of patriarchal power to that of class oppression and ethnic 'othering'.