Stereo pairs of contour maps may be constructed by a process analogous to, but the inverse of, the process used to make contour maps from stereo pairs of aerial photographs. This construction can be carried out either manually or with computer plotting devices. The contoured stereo pairs are then viewed in three dimensions by a variety of methods: with lens or mirror stereoscopes, with bicolor anaglyphs in drafted, printed, or projected form, or by polarized light methods. Preferred techniques at present are 1) 5-inch wide prints viewed by the mirror stereoscope, and 2) anaglyphic rear projection on a 3 X 4 ft screen.The advantages of studying complex contour maps in three dimensions are striking. The entire morphology of the map may be studied rapidly by the human optical system, the latter carrying out such functions as trend filtering, wavelength filtering, form and texture recognition, and location of linears almost simultaneously. Important features that are missed or seen with difficulty on the flat contour map become obvious in a three-dimensional view, and may be studied further in detail by manual or computer techniques.The method appears to be a significant interpretational breakthrough, bringing us one step closer to a total interpretation, wherein all observable map features are correlated with their geological causes.