Within a few short years, drones went from being a niche capability reserved for technically advanced militaries to something ubiquitous on the modern battlefield.  According to the Atlantic Council, Ukraine was producing 200,000 first person view drones per month by early 2025.  The Ukrainians used those drones to inflict up to 80% of Russian battlefield casualties.  That conflict continues and so does its use of drones.  Meanwhile, Hamas used drones to as part of the October 7th attacks.  The Houthis have used drones to attack US Navy ships in the Red Sea and drones are being extensively used by Iran in the ongoing conflict.  Drones are a rapidly changing and rapidly proliferating capability.  In this book, engineer and historian Lars Celander gives an overview of how drones are designed and used – How they fight.