Using geophysical methods in the study of contaminated sites has gained wide acceptance, yet the multiplicity of available methods, the use of differing terms, & the high degree of technical proficiency required for the application & interpretation of data often causes confusion. This guide describes both commonly used & less common geophysical methods in relatively nontechnical terms, & provides guidance in finding detailed information on specific methods, information on designing & evaluating a geophysical program, & summary case study information on the use of surface & borehole methods.