This book will introduce the basics of internet of things (IoT), and bring out the foundational role of sensors in internet-of-things applications. Internet of things is a network of devices and objects: sensors, actuators, hardware, software, human beings, domestic appliances, health monitoring equipment, and other things connected to the internet, which is designed to operate in a coordinated fashion to receive, process and interpret signals and take appropriate action. It aims to provide a seamless real-time interface between the physical and digital worlds by integrating sensors with networking, computation and actuation facilities.This book will sketch a perspective of IoT with sensors at the focus of attention. Diverse applications of IoT that are destined to make an impact on our everyday lives in near future will be discussed. It will be a comprehensive overview of the most recent sensor technologies used in internet of things to make the reader abreast of the current advances at the frontiers of knowledge. The book will cater to both audiences and will be useful for postgraduate and Ph. D students studying physics, engineering, and computer science as well as professional researchers, engineers and industrial workers engaged in this fast progressing field.