In this paper the authors present surface rheol. measurements of various surfactant solns. close to equil. in a Langmuir trough. The authors find that the storage modulus is, in the systems investigated, higher than the loss modulus. The rheol. behavior depends strongly on the surfactant concn., even at concns. exceeding the CMC. Films with quite different surface rheol. properties show similar drainage rates. This supports earlier work (1992), in which the velocity of film drainage was detd. by bulk viscosity effects. A no. of possible explanations for the cause of the surface rheol. effects found in the authors' solns. are examd. The rheol. effects at concns. exceeding the CMC can best be ascribed to two-dimensional ordering of surfactant mols. at the surface combined with interaction of these mols. with micelles in the nearby soln.