The great research effort that has been mobilized to attempt solution of lunar exploration problems involving properties of soils and rocks on the Moon is summarized and reviewed. Current (1963) research activity has been examined within the framework of five categories: (1) Exploration and mapping of the lunar surface; (2) lunar soil formation and the general nature of surface materials; (3) simulation of lunar soils; (4) theoretical and experimental determination of lunar soil properties and soil mechanics; and (5) landing and mobility problems, construction problems, and soil stabilization. Several possible lunar soil types have been postulated; however, most research is being carried out on loose, cohesionless, fine-grained materials subjected to the postulated lunar environment of high vacuum and low gravity. The major factor limiting the direct application of the results of these studies to the solution of lunar exploration problems, such as the design of spacecraft landing gear, is the lack of specific data on the nature of lunar soils and surface roughness.