The book of Bonabeau, Dorigo, and Theraulaz is an excellent example of synergetic work between a physicist, an engineer, and a biologist. The Swarm Intelligence principles are first described and understood through models in natural systems and then translated in optimization algorithms, distributed algorithms for robotic control, and so on. Even if the book does not completely succeed in linking all three disciplines together - computer science, engineering, and biology - under a sound, common formalism, it represents an extremely up to date collection of work carried out worldwide in the field of Swarm Intelligence. I strongly believe in the future of this field and of its applications to problems hard to tackle with classical techniques. This book summarizes in an very equilibrated way the early, promising steps of Swarm Intelligence.