This book examines the relationships among leadership, the quality of the management process and business results. Drawing from the pioneering contributions of Chester I. Barnard, this book defines the role and characteristics of an effective and efficient manager in the new knowledge economy. This book also examines the relevance of Barnard’s work on modern studies in economics and business administration. Chester I. Barnard considered the company to be a complex socio-economic system, oriented towards general aims. A company’s behavior is rational if its constituent elements and management models are planned, organized, guided and regulated in order to create and maintain a cooperative system that combines efficiency and effectiveness. In this book, the conceptual construction of Barnard’s management theory is represented by a synthetic scheme in which the various components of the business process (including leadership) and their influences on the outcome variables of the company are linked as a system. This approach makes this book appealing to academics, scholars and professionals in business, management, administration and knowledge management.