This book describes recent developments in soil liquefaction engineering and introduces more appropriate procedures than the current ones to evaluate triggering and consequences of soil liquefaction during earthquakes. The topics therefore cover all aspects of soil behaviour following liquefaction during earthquakes. The contents start with new approaches and new findings on characterisation of liquefaction resistance and undrained shear strength of fully saturated, partially saturated, and unsaturated sand, which are fully based on laboratory tests. New approaches and findings are then described on the use of in situ sounding tests for characterising triggering and consequences of soil liquefaction, including post-liquefaction settlement, lateral spreading, and stability against flow slide. All the topics are accompanied by illustrative case history data from recent major earthquakes in Japan.