Near-surface geophysics is being applied to a broader spectrum of problems than ever before, and new application areas are arising continually. Currently, the tools used to examine the near-surface environment include a variety of noninvasive methods employing electrical, electromagnetic, or mechanical energy sources, along with passive techniques that measure the physical parameters of the earth. Some of the advances of recent years have emerged from breakthroughs in instrumentation and computer-processing techniques, and some have been driven by societal needs, such as the increasing demand for the accurate geophysical characterization of polluted sites. Other compelling factors, such as the ever-expanding need for groundwater, the enactment of laws that have spurred geophysical surveying for archaeological purposes, and the necessity for better soil-physics information in geotechnical engineering and agriculture, are present worldwide. For historical context, the reader is referred to an excellent review concerning the status of shallow exploration techniques in the mid-1980s (Dobecki and Romig, 1985).