Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138
In this century, various ground-based interferometric techniques have
been developed and applied to precise measurement of the angular sizes of a large
number of variable stars. In this paper I describe the interferometric approach to
variable star studies, highlight results from several interferometric surveys of long
period variable stars and Cepheids, and discuss future challenges in high angular
resolution variable star research.