The purpose of this study was to develop a theory for clay deformation that models the behavior represented by Bjerrum's time lines (Bjerrum (1961). The theory models time-dependent compression (secondary compression) and the "aging" effect, or increase in preconsolidation pressure with time under sustained load. The theory appears to be consistent with many aspects of the consolidation behavior of real clays, including: (1) secondary compression, (2) aging, (3) different values of Cv determined by Casagrande's method and Taylor's method, and (4) faster settlement in the field than expected on the basis of conventional theory. It thus appears to have considerable potential for use in interpreting laboratory tests and predicting field settlements more accurately than has been possible up to the present time. In addition to development of the new theory, the study involved an extensive review of previous work and suggestions for possible future studies." 14. The results of this study lead to the conclusion that the OWL model did prepare the Shawsville children for first grade experiences and that their achievement would be at least as good as those children who participated in a traditional kindergarten program. / Ph. D.