Programmable matter is probably not the next technological revolution, nor even perhaps the one after that. But it's coming, and when it does, it will change our lives as much as any invention ever has. Imagine being able to program matter itself-to change it, with the click of a cursor, from hard to soft, from paper to stone, from fluorescent to super-reflective to invisible. Supported by organizations ranging from Levi Strauss and IBM to the defence Department, solid-state physicists in renowned labouratories are working to make it a reality. In this dazzling investigation, Wil McCarthy visits the labouratories and talks with the researchers who are developing this extraordinary technology, describes how they are learning to control it, and tells us where all this will lead. The possibilities are truly astonishing.