PROSPECTOR was developed to aid the geologist in evaluating the mineral potential of a site or an area. Recent developments include enhancements of the existing PROSPECTOR program and the creation of two new programs, muPROSPECTOR and HYDRO. It is predicted that PROSPECTOR and similar programs will develop most rapidly for applications which geologists feel ill-prepared to handle unaided and for focusing on undetected deposits for which more systematic evaluation of geologic, geochemical, and geophysical data are required.