Geologic maps supply a wealth of information about the surface and shallow subsurface of the earth. The types of materials that are present in a location and the three-dimensional structure of the bedrock both can be gleaned from a clearly prepared geologic map. Geologists, civil and environmental engineers, land-use planners, soil scientists, and geographers commonly use geologic maps as a source of information to facilitate problem solving and identify the qualities of a region. Maps reveal the position of many types of natural hazards, indicate the suitability of the land surface for various uses, reveal problems that may be encountered in excavation, provide clues to the natural processes that shape an area, and help locate important natural resources. Suitable for lab courses in structural geology as well as field geology work, Spencer describes representative examples of features found on geologic maps and outlines procedures for interpretation and projection. Geometric techniques are explained using a step-by-step approach. Coverage of mapping methods includes tools that provide necessary data, such as Google Earth, GPS, GIS, LiDAR maps, drones, and aerial photographs. Challenging and engaging exercises throughout the text involve students in the mapping process and stimulate an appreciation of the extent and precision of information presented in geologic maps. Regional geology is an important component of lab and field mapping projects. As such, the Third Edition includes new maps of the Gulf of Mexico Coastal Plain, Rocky Mountain Front Range, Yellowstone region, Moab, Utah, Shenandoah National Park, and Hawai’i. A new chapter devoted to tectonic maps also broadens students’ exposure. Ed Spencer brings over 45 years of teaching experience to the text along with valuable insight and clarity into the interpretation and preparation of geologic maps.