These proceedings contain eight keynote lectures which were presented by Dutch specialists at the 20-year Jubilee symposium of the Netherlands Ingenieurgeologische Kring. These lectures covered: developments in engineering geology in the Netherlands; engineering geophysical data collection techniques; unconventional sounding and sampling techniques; classification and characterization of soft soils; geostatistics in holocene deposits; modelling of unconsolidated sediments; environmental engineering geology; and the use of underground space in deltaic areas.