There are several reasons for interest in self- assembly (1, 2). First, humans are attracted by the appearance of order from disorder. Second, living cells self-assemble, and under- standing life will therefore require under- standing self-assembly. The cell also offers countless examples of functional self-assem- bly that stimulate the design of non-living systems. Third, self-assembly is one of the few practical strategies for making ensembles of nanostructures. It will therefore be an es- sential part of nanotechnology. Fourth, man- ufacturing and robotics will benefit from ap- plications of self-assembly. Fifth, self-assem- bly is common to many dynamic, multicom- ponent systems, from smart materials and self-healing structures to netted sensors and computer networks.