This paper is generally concerned with presenting a broad overview of the capabilities, limitations, and potential uses of the vacuum ultramicrobalance for Surface studies. Determination of micromass changes of samples in vacuum and controlled gaseous environments at various temperatures is one of the powerful methods for studying surfaces. The traditional application of the vacuum microbalance and accompanying theoretical foundation for obtaining surface areas, activation energies of adsorption and desorption, the heat of adsorption, and the initial stages of oxidation are reviewed. As with most physical measurements, the simultaneous measurement of mass change and other parameters greatly increases the ability to understand physical and chemical processes. Examples of the combined measurement of residual gases, infrared spectroscopy, and electrical properties as well as the mass change are presented. Recent progress in developing an automated ultramicrobalance for operation in a UHV system combined with RGA and AES is discussed. Information about specific gas-solid systems is presented to illustrate the utility of the microbalance.