As a first step in the microscopic study of dynamic processes on surfaces and at interfaces, we have considered the thermal desorption of adsorbed species on solid surfaces. We review recent developments based on a classical stochastic diffusion formulation. Using this theory, we obtained a simple rate expression,R=(Ω0/2π)f(T)exp(−De/kT), where Ω0is the surface‐adsorbate vibrational frequency andDethe dissociation energy. For atomsf(T)=1, whereas for moleculesf(T) depends on the parameters for the frustrated rotations at the surface. The effect of coverage on the rate of desorption and the process of desorption into a fluid are also examined. Finally, we discuss the relationship between our theory and the expressions obtained from activated complex (transition‐state) theory.