In order to truly understand software and the software development process, software measurement must be better understood. A beginning step toward a better understanding of software measurement is the categorization of the measurements by some meaningful taxonomy. The most meaningful taxonomy would capture the basic nature of the subject oriented (O-O) space. The interesting characteristics of object oriented software offer a starting point for such a categorization of measures. A taxonomy has been developed based on fourteen characteristics of object-oriented software gathered from the literature This taxonomy allows us to easily see gaps and redundancies in the O-O measures. The taxonomy also clearly differentiates among taxa so that there is no ambiguity as to the taxon to which a measure belongs. The taxonomy has been populated with thirty-two measures that have been validated in the narrow sense of Fenton, using measurement theory with Zuse's augmentation. Neal, Ralph D. NASA-CR-203088, NAS 1.26:203088, NASA-IVV-96-021, WVU-SRL-96-021, WVU-SCS-TR-96-32 NCCw-40...