In our solar system, there are hundreds of objects trapped in orbit around the planets. These moons feature some of the most extreme and fascinating environments-from Enceladus's organic compound rich jets to Titan's methane lakes and thick atmosphere. Some of these environments may even be conducive to life. Author Ron Miller, who is also a NASA illustrator, delves into the science behind these underexplored objects and makes the case for why moons should be the first place we look for alien life.