Cultural changes over the past two decades have led to a proliferation of new social movements in Europe and the United States. New social movements such as ecology, peace, ethnicity, New Age philosophies, alternative medicine, and gender and sexual identity are among those that are emerging to challenge traditional categories in social movement theory. Synthesizing classic and modern perspectives the contributors help to redefine the field of social movements and advance an understanding of them through cross-cultural research, comparison with older movements, and an examination of the dimensions of identity—individual, collective, and melding of the two.