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This is an abstract for a talk to be given at the Fifth Foresight Conference on Molecular Nanotechnology. There will be a link from here to the full article when it is available on the web.A perfect quantum wire would have truly one-dimensional electronic properties, and would open many possibilities for advanced high performance electronic devices. A crucial factor in the performance is the straightness of the wire; both roughness and compositional imperfections degrade the quantum conductance by inducing localization of electrons. We have discovered a way to use nonequilibrium aspects of desorption processes to fabricate atomically perfect wires of bismuth atoms in a Si(001) surface. The wires can be made either by first covering a Si(001) surface with a monolayer or so of Bi and then heating it until most of the bismuth desorbs, or by depositing Bi on a Si(001) surface at a temperature at which the desorption rate is close to the incident flux. Because of the inherent stability of the wires, the temperature for Bi desorption from them is higher than from the surface as a whole. We can observe the formation of these wires by making atomic movies in an elevated temperature scanning tunneling microscope. The wires are 1 nm wide, hundreds of nm long, and absolutely straight. They are atomically perfect: there are no kinks or missing dimers in any of the wires.