The result of half a century of research and experimentation in economics and management, this Treatise is intended for management practitioners. Socio-economic management (SEAM) makes the demands of humanism in professional life and sustainable economic prosperity compatible. It is illustrated with numerous cases from 2,150 companies and organizations from a wide variety of sectors and presents observed and measured results. Most of these chapters are written jointly by managers or executives of companies and organizations, and scholars or consultants involved in the pilot actions. This book is the work of 193 authors, from 16 countries and 4 continents, practitioners or academics in management sciences and management. This reflects the diversity of national and sectoral contexts of SEAM applications. Some chapters situate this concept in relation to the major currents of current thought. Each chapter is preceded by abstracts in French, English and Spanish. The prefaces, signed by Herman Aguinis and René Ricol, show the scope of socio-economic theory and management beyond the borders of the company. The book illustrates the international influence (48 countries) of the innovative and robust methods created and developed by the ISEOR team. Socio-economic theory constitutes a "breakthrough innovation", both in terms of its conceptual contribution and the practical methods and tools of its applications. This holistic approach touches on the different functions of the company and its multiple problems. It provides a structured change management method, focused on stimulating Human Potential and on self-financing the development of the company or organization, through the periodic recycling of hidden costs.