Most of us have had the experience of running into a friend of a friend far away from home - and feeling that the world is somehow smaller than it should be. We usually write off such unlikely encounters as coincidence, even though it seems to happen with uncanny frequency. According to a handful of physicists at Los Alamos and other cutting-edge research labs around the world, it turns out that this 'small-world' phenomenon is no coincidence at all. Rather, it is a manifestation of a hidden and powerful design that binds the world together. In SMALL WORLD, Mark Buchanan tells the story of how a stunning discovery in complexity science is revolutionising the way we understand networks. The Internet, the brain, power-grids and the global economy are all networks that seem to have evolved a 'small-world' geometry - with properties independent of the nature of the things themselves. SMALL WORLD argues that this underlying pattern may be one of nature's greatest design tricks, and the book shows us - concisely and engagingly - how scientists are putting this new insight to work. The discovery promises to change the way we see the web of relationships that weaves our lives together. What's more, it may well provide the foundation for a new kind of physics that searches for the laws not of substance, but of pure form.