Computers built from DNA, bacteria, or foam. Robots that fix themselves on Mars. Bridges that report when they are aging. This is the bizarre and fascinating world of Natural Computing. Computer scientist and Scientific American's “Puzzling Adventures” columnist Dennis Shasha here teams up with journalist Cathy Lazere to explore the outer reaches of computing. Drawing on interviews with fifteen leading scientists, the authors present an unexpected vision: the future of computing is a synthesis with nature. That vision will change not only computer science but also fields as disparate as finance, engineering, and medicine. Space engineers are at work designing machines that adapt to extreme weather and radiation. “Wetware” processing built on DNA or bacterial cells races closer to reality. One scientist's “extended analog computer” measures answers instead of calculating them using ones and zeros. In lively, readable prose, Shasha and Lazere take readers on a tour of the future of smart machines.