Humans have long been fascinated by ants. While not necessarily brightly coloured or beautiful, ants display some remarkable characteristics that are almost unique in the animal world. They live in intricately organized societies, made up of individuals that cooperate, communicate, and divide up daily tasks. They display amazing ingenuity when it comes to building nests and other structures, finding supplies, or even exploiting other members of the animal kingdom. They are capable too of aggression and violence, of disturbing the apparent peace of their colonies and of sudden fratricidal or matricidal strife. In short, the lives of ants are among the most fascinating in the natural world. This is an account of those lives - looking at the many species of ants around the world, explaining the secret of their huge ecological success, examining the remarkable and varied behaviours that ants exhibit, and tying in molecular biology, genetics, and even cutting-edge developments in robotics, to shed light on what makes ants unique.