Amorphous materials give rise to rather diffuse diffraction patterns. In contrast to diffraction patterns from polycrystalline materials which are characterized by a large number of sharp diffraction rings, patterns from amorphous materials are composed of relatively few broadened features. Such a diffuse pattern, however, contains much structural information in the form of an interatomic distance distribution that may be computed directly from the measured diffraction pattern. This radial distribution function (RDF) provides information concerning bonded distances, the types of atomic groupings and the extent of ordering in the sample. Special care, however, must be taken during the analysis to avoid introducing spurious details into the RDF that may be confused with, or mask real structural features. Such false detail may arise both from data collection and data reduction procedures. The availability of modern computers has greatly facilitated the calculation of accurate RDF's by readily permitting the introduction of physical criteria into the data reduction procedure that must be satisfied by the RDF.