By focusing on the mechanical behavior of geomaterials observed by means of laboratory tests, we have attempted to survey the 50 year history of relevant studies presented in Soils and Foundations and to introduce some of the recent research outcomes. First, the developments of a variety of testing apparatuses and procedures are summarized, with a particular focus on the eŠects of boundary conditions and sample disturbance, local and microscopic measurements, and the observation of small strain behavior as well as large strain behavior. Second, studies on the properties of sandy soils, clayey soils, other problematic soils and cemented soils including aged soils and soft rocks, respectively, are reviewed brie‰y. Third, because it is a research topic that has had the attention of so many researchers for so long, and some remarkable progress has been achieved recently, studies on viscous behavior, including the dependency on the loading rate and creep deformation, are overviewed.