Retells the history of the radical left during the twentieth century through the words and deeds of Paul Mattick. In Marxism in a Lost Century, Gary Roth retells the history of the radical left during the twentieth century through the words and deeds of Paul Mattick. An adolescent during the German revolutions that followed World War I, he was also a recent migrant to the United States during the 1930s Great Depression, when the unemployed groups in which he participated were among the most dynamic manifestations of social unrest in the country's history.