Why do similar patterns and forms appear in nature in settings that seem to bear no relation to one another? The windblown ripples of desert sand follow a sinuous course that resembles the stripes of a zebra or a marine fish. In the trellis-like shells of microscopic sea creatures we see the same geometry as in the bubble walls of foam. Forks of lightning mirror the branches of a river network or a tree. This book explains why these are not coincidences. Nature commonly weaves its tapestry without any master plan or blueprint. Instead, these designs build themselves by self-organization. The interactions between the component parts - whether they be grains of sand, molecules or living cells - give rise to spontaneous patterns that are at the same time complex and beautiful. Many of these patterns are universal, recurring again and again in the natural order: spirals, spots, stripes, branches, honeycombs. Philip Ball conducts a profusely illustrated tour of this gallery, and reveals the secrets of how nature's patterns are made.