This publication contains the papers presented at the 15th European Conference on Soil Mechanics and Geotechnical Engineering (ECSMGE), held in Athens, Greece. Considerable progress has been made in recent decades in understanding the engineering behavior of those hard soils and weak rocks that clearly fall into either the field of soil or of rock mechanics, and there have been important developments in design and construction methods to cope with them. Progress would be even more desirable, however, for those materials which fall into the 'grey' area between soils and rocks. They present particular challenges due to their diversity, the difficulties and problems arising in their identification and classification, their sampling and testing and in the establishment of suitable models to adequately describe their behavior. The publication aims to provide an updated overview of the existing worldwide knowledge of the geological features, engineering properties and behavior of such hard soils and weak rocks, with particular reference to the design and construction methods and problems associated with these materials. Part 4 was published post-conference and includes Conference Reports.

The 16th ICSMGE responds to the needs of the engineering and construction community, promoting dialog and exchange between academia and practice in various aspects of soil mechanics and geotechnical engineering. This is reflected in the central theme of the conference 'Geotechnology in Harmony with the Global Environment'. The proceedings of the conference are of great interest for geo-engineers and researchers in soil mechanics and geotechnical engineering. Volume 1 contains 5 plenary session lectures, the Terzaghi Oration, Heritage Lecture, and 3 papers presented in the major project session. Volumes 2, 3, and 4 contain papers with the following topics: Soil mechanics in general; Infrastructure and mobility; Environmental issues of geotechnical engineering; Enhancing natural disaster reduction systems; Professional practice and education. Volume 5 contains the report of practitioner/academic forum, 20 general reports, a summary of the sessions and workshops held during the conference.