This paper presents a review of developments in scaling theory from 1954-1957. Current controversies regarding the limitations of measurement theories are briefly discussed. The following topics are then considered: 1) axiomatic models; 2) decision process and utility measurement; 3) Coombs' models and methods; 4) paired comparison models; 5) categorical judgment methods; 6) psychophysical scaling; 7) multidimensional scaling; 8) Guttman scale analysis; 9) latent structure analysis; and 10) criteria for scale evaluation. It is suggested that scale theory should recognize multiple criteria for the goodness of a scale and that these criteria should include replicability, internal consistency, coordinating power, and most especially, appropriateness as a psychological model. It is further suggested that scaling methods be classified as either deterministic or stochastic models (roulette-wheel or urn models, confusion models, dynamic vacillation models and non-committal models), and the various models discussed here are so classified. Problems and limitations of all the models are mentioned. (JGL)