Aircrafts that work without any human pilot on board are known as unmanned air vehicles. These are the component of an unmanned aircraft system. They can be classified into six broad categories that are target and decoy, reconnaissance, combat, logistics, research and development, and civil and commercial. The flights of such vehicles can either be controlled by a remote control that is operated by a human, or they work autonomously with the help of the computers present on board. Unmanned air vehicles are often used for the missions that are too dangerous for humans. Initially, they were mostly used in dangerous military operations, now they are used to fulfill commercial, agricultural and scientific needs such as policing, peacekeeping, drone racing, aerial photography or product deliveries. This book explores all the important aspects of unmanned aerial vehicles in the present day scenario. The various advancements in the field are glanced at and their applications, as well as ramifications, are looked at in detail. This book attempts to assist those with a goal of delving into this field.