The study of opinion dynamics is helpful to reveal the essential characteristics of the phenomenon of opinion and the deeper reasons and rules behind the features. Normally, opinion dynamics utilizes continuous models, discrete event and agent-based modeling methods to describe the interactive behaviors among individuals and explain opinion formation and evolution dynamics. Most existing works focus on opinion transition from disorder to order or vice versa, but the network topology issue is less scrutinized. To tackle this problem, this book combines complex network theory with opinion dynamics to study and reveal the underlying mechanisms of multi-agent opinion formation. That is, the effect of social network structure to opinion dynamics is studied. The network characteristics include its connection topology, i.e., hierarchical tree, small-world, scale-free and fully connected networks; its type and scope include formal and informal; heterogeneity and homogeneity of opinion changing threshold etc.