Internet of Things is a textbook designed for students of computer science, information technology and electronics & communication engineering to understand the interconnection and integration of the physical world with the cyber space and begin designing and developing simple IoT devices. Divided in to five parts, the book in nineteen chapters takes the reader through the foundations of the subject before moving onto discussing the essential components of an IoT system, including the sensor and actuators, open hardware, middleware, and software platforms with sound illustrations for better understanding. It also dedicates a complete module comprising four chapters on IoT and its relevance to Big Data. The last two parts of the book focuses on data management and use cases finally ending with the chapter on futuristic outlook of this technology.