This book presents the foundations of three theories that analyze the motivations of people who commit Economic Crimes - the Anomie Theory, the Opportunity Theory and the Neo-Marxist Theory - as opposed to the assumptions of the Economic Theory of Crime. The methodological base was a diversified bibliographical referential and the information obtained through the answers of men and women who served prison sentences to a form with questions that cover since their familiar environment until the way they see the Institutions.