Swarm intelligence is an innovative computational way to solve hard problems. This discipline is inspired by the behaviour of social insect (e.g. ants, termites, bees and wasps) colonies as well as fish schools and bird flocks. The content of this book is divided into two main parts: ant colony optimisation and particle swarm optimisation. The former describes systems that have been engineered using ant colony optimisation and the latter presents systems that were designed based on particle swarm optimisation.