Unmanned aerial vehicles (UAVs), commonly referred to as drones, have irrevocably altered the scene of modern warfare. Their proliferation across the globe, employed by both state and non-state actors, necessitates a thorough understanding of their capabilities, limitations, and implications for military strategy and international security. This book serves as a foundational introduction to the world of drone warfare, providing a comprehensive overview of the technology, its applications, future technologies development and its far-reaching consequences. Current UCAVs rely heavily on human operators for decision-making, even in semi-autonomous modes. Future generations, however, will likely feature increasingly sophisticated AI systems capable of autonomous target recognition, engagement prioritization, and even strategic decision-making within pre-defined parameters. This increased autonomy will not only enhance the speed and efficiency of operations but will also enable UCAVs to react more swiftly to dynamic battlefield situations. The integration of advanced data fusion algorithms will further enhance situational awareness, enabling UCAVs to more effectively process and interpret data from multiple sources. This will allow for a more comprehensive and accurate understanding of the battlefield, enabling more informed decision-making. The integration of drones with autonomous vehicles, such as self-driving cars and trucks, opens up yet another exciting area of collaborative autonomy. While aerial drones dominate headlines, the silent, persistent operation of unmanned surface vessels (USVs) is quietly revolutionizing naval capabilities, particularly in surveillance and mine countermeasures (MCM). The use of autonomous underwater vehicles (AUVs) in conjunction with USVs significantly enhances MCM capabilities. The international implications of drone warfare are equally profound. The use of drones by certain nations has powered international tensions and prompted accusations of violating national sovereignty. The unilateral nature of drone strikes, often carried out in the territories of other countries without explicit consent or notification, has generated significant resentment and anger amongst affected governments. The impersonal nature of drone warfare, often described as "video game warfare," can ironically amplify this moral injury, as the lack of physical immediacy can create a psychological distance that prevents necessary emotional processing and resolution.