This book provides a concise modern introduction to the science of complex networks. The book is based on lectures for university students and non-specialists. The aim is to introduce the world of networks to the subject without need for a serious background in mathematics or physics. The introductory chapters fill the existing gap between popular science books and comprehensive reference volumes on complex networks (including the Internet, World Wide Web, etc.). The book provides the shortest path to the world of networks and discusses the main directions of modern research in this active field as well as the history of network studies. The book describes the current state of the art in complex networks and includes recent results.