In the name of nationalist ideologies, unimaginable crimes have been committed. On the other hand, movements under the banner of national liberation have freed their peoples from colonial oppression. Michael Löwy, a representative of a critical and open Marxism, examines the significance of national movements for Marxist theory and socialist workers' parties. He highlights the key points of the views of Marx and Engels, Rosa Luxemburg, Lenin, Leon Trotsky, Anton Pannekoek, Otto Bauer, and others. In additional essays, he addresses current national conflicts and explores the possibilities of a new internationalism.