In an effort to put more science into the largely trial and error building of nanostructures, physicists at the Commerce Department's National Institute of Standards and Technology (NIST) have demonstrated new methods for placing what are typically unruly individual atoms at precise locations on a crystal surface. Reported in the Sept. 9, 2004, online version of the journal Science, the advance enables scientists to observe and control, for the first time, the movement of a single atom back and forth between neighboring locations on a crystal and should make it easier to efficiently build nanoscale devices "from the bottom up," atom by atom.