This book was first published in 2007. In recent years network science has become a dynamic and promising discipline; here it is extended to explore social and historical phenomena. While we experience social interactions every day, there is little quantitative knowledge on them. Instead we are often tempted to resort to fanciful explanations to explain social trends. Exogenous and endogenous interactions are often the key to understanding social phenomena and unravelling historical mysteries. This book begins by explaining how it is possible to bridge the gap between physics and sociology by exploring how network theory can apply to both. It then examines the macro- and micro-interactions in societies. The chapters are largely self-contained, allowing readers easily to access and understand the sections of most interest. This multi-disciplinary book will be fascinating to all physicists who have an interest in the human sciences and it will provide an alternative perspective to graduate students and researchers in sociology and econophysics.