Unit and ubiquitous internet of things Preface Internet of Things (IoT) attracts great attention and brings promising opportunities and challenges. Research on IoT has important economic and social values for the development of the next generation of information network and communication technologies. However it is still confusing for most people to understand IoT well including definitions contents and differences from other similar concepts. IoT connects and fuses the physical world and cyber world by ubiquitous sensing connection and control with definite social attributes. It is hopeful that IoT can emancipate humans from onerous humanmachine interface work and information exploration. This book attempts to provide a future IoT vision and answer some fundamental questions from various aspects including concepts architectures models and key technologies. It aims at helping readers find out the fundamental issues in IoT and to be valuable IoT literature for college students practicing engineers researchers business operators and policy makers. The book accomplishes three main objectives Introduce IoT essential concepts and contents from the perspectives of mapping and interaction between the physical world and cyber world. Meanwhile social attributes are emphatically discussed in IoT. Preface Build a fundamental architecture for future IoT based on which the IoT layered model topological structure various existence forms and corresponding logical relationships are described. Specific case studies are also presented in different application scenarios