The University of Illinois' PLATO Elementary Program, which was observed and evaluated for two years, was the focus of Part 1. The major PLATO features were described and the PLATO elementary reading and mathematics demonstrations, representing attempts at sequential and concurrent hardware, software, curriculum, and implementation development of tutorial computer assisted instruction, emphasized. The PLATO staff was composed of volunteers because of the perceived importance of teacher commitment to the program. This method of selection caused several problems. The orientation of PLATO staff varied with implementer's views of proper teacher contribution to the program. Judgments on the effectiveness of teacher orientation and the relationship between that process and the eventual development of the innovation were inconclusive. In Part 2, the theoretical components of the degree of PLATO implementation and classroom observation were discussed. An effort was made to sketch the evolution of one of the observation instruments being employed to observe the effects of PLATO on the life of elementary classrooms, the conditions and hypotheses under which it has been developed and used, and one illustrative result concerning implementation. (BJG)