The Conference on Frontiers in Research and Practice in Plain Conerete was held at the University of Illinois Conference Center. Robert Allerton Park. Monticello., Illinois, USA, from September 8 through 11, 1970. The program consisted of a series of introductory lectures and discussion on topics pertinent to conerete research. The topics and the discussion leaders were as follows: 1) The Engineering Challenge to Conerete Georg Verbeck, Portland Cement Association 2) Recent Developments in Understanding the Matrix of Conerete Brady Williamson, University of California 3) Mechanics of Conerete (stress and strain of multiphase materials). The Strength of Conerete as a Multiphase Material Joseph Glucklich, Israel Institute of Technology 4) Effeet of Extreme Environments on Concrete (wetting and drying; low and high temperature), Peter Smith, Ontario Department of Highways 5) Moisture Migration in Conerete Hubert Hilsdorf, University of Illinois 6) Recent Developments in Cements, Paul Klieger, Portland Cement Association The Conference was concerned with plain conerete - as opposed to reinforced concrete, and with research - as opposed to structural design or construction practice. The aim of the presentations and discussions in the conference were to contribute to the understanding of the fundamental nature of plain concrete. The presentation of new developments and new concepts was emphasized without undue review of previously published observations and analyses. The purpose of the conference was to bring together scientists and engineers, engaged in basic research and use of plain conerete and in allied fields, to exehange ideas in a free and informal atmosphere. The list of the participants has been influded as an appendix. The papers of this publication are the contributions distributed by the author to the participants in the above mentioned conference. Report on the Conference will be published by the University of Illinois in due time, probably during the first half of 1971.