FOREWORD: The mission of the ACI 125 Committee is to develop and correlate knowledge and formulate recommendations for concrete construction on the Moon. This symposium volume contains the first series of papers dealing with the topic. The papers address cement production@ concrete mixes@ structural concepts@ concrete placement@ and the lunar environment. Man's earlier exploration of the Moon during the Apollo program involved brief sorties from the flight vehicle@ which served as the astronaut's lunar habitat. One of the objectives of the Space Exploration Initiative (SEI) is to establish permanent outposts on the Moon. These outposts will require permanent facilities. Ideally@ these facilities can be constructed with maximum utilization of indigenous materials@ such as lunar concrete.