The rapid increase in the development of land, the exploitation of minerals, and the related accelerated environmental impacts have caused an explosion of demand for information that can be used as a guide to land use decision-making. “Environmental Geology Mapping” was the topic of an engineering geology symposium at the 1972 annual meeting of The Geological Society of America; natural resources planning and the roles and interrelations of geology and geologists, planning and planners were discussed. This book presents the coverage of those subjects because of their continuing timeliness and the need for a reminder that we must provide data that are relevant and usable for interdisciplinary considerations in natural resources planning. The authors express their ideas on how to translate professionally the traditional, basic earth-science data into forms that are adaptable to interdisciplinary solutions of environmental problems. They unanimously state that this conversion of data has to result in a viable input for decision-making, and it must also stand the scrutiny of the real world; that is, it must receive public endorsement and support.