During the past year, much speculation has centered on the possibility of separating isotopes by the use of lasers. The technique seems to promise very efficient separation processes that could revolutionize the economic aspects of the preparation and the use of isotopes. 1 The most important application of such a method would be in the enrichment of uranium for use in nuclear power reac-tors. 2 There are, however, other applications for pure isotopes if an enrichment technique can be found that can produce large quantities cheaply. We shall describe the various laser separation processes, review the existing work, and attempt an assessment of its economic possibilities.