Aerial robots can be considered as an evolution of the Unmanned Aerial Vehicles (UAVs). This book provides a quite complete overview of issues related to aerial robotics, addressing problems ranging from flight control to terrain perception and mission planning and execution. The major challenges and potentials of heterogeneous UAVs are comprehensively explored. It builds on the results of the European project COMETS, and highlights a number of key research topics in the area of UAV development, including communication, perception, teleoperation and decision making. The monograph emphasizes the current state of technology, the existing problems and potentialities of systems consisting of multiple UAVs which are heterogeneous in view of the different characteristics of the aerial vehicles, the different on-board payloads, and the different on-board information processing capabilities. The book also examines potential applications of UAVs and details a relevant application case: forest fire detection and monitoring.