The continuous increase in the diversity and complexity of economic and financial transactions, at both the national and transnational level, is leading to a continuous dynamic of business organizations and reorganizations. Thus, some of the practical forms adopted are the formation of groups, associations and other organizational forms, which implies the production of significant mutations in the standards and regulations in the field at national and international level. The aim pursued in this book is to familiarize the reader with the notions related to the group.