The effectiveness of prephonic training between kindergarten and first grade levels as a tool for acquiring reading skills was explored throughout the public school system in the city of New Bedford, Massachusetts. A sample population of 260 kindergartners was identified as having potential learning difficulties by the results shown on the Slingerland, Mahon and Metropolitan Readiness Tests. This sample was randomly assigned to either Group one, experimental, or to Group two, control. The research design applied was the Campbell and Stanley number 6, posttest two group design. Group one received the Mahon System of assistance given by teacher aides trained by Dr. Mahon. Group two received only the assistance based upon current reading materials used in the entire school system. Time allotment was half an hour a day for each group. The results of the posttest confirmed the value of prephonic training where early diagnosis had identified potential learning difficulties. As a by product, the areas of early identification found to be most appropriate for individualized instruction were revealed. [Marginal reproducibility of some pages.] (Author)