[en] Part 1 of this Handbook is focused on description of fundamental issues of soil physical and chemical arts and on soil mechanical definitions and relationships. Part 2 comprises a material data basis including also preparation and field testing methods. Part 3 provides a collection of physical and mathematical models and examples of how they can and should be applied. The present document, which has been prepared by Geodevelopment AB in co-operation with Scandia Consult AB and Clay Technology AB, Sweden, and with TVO, Finland, makes up Part 1. Most of the data and information emanate from the work that Geodevelopment AB and Clay Technology AB have performed for SKB but a number of results from experiments made in and for other organizations have been included as well. A significant number of experimental procedures and ways of characterizing buffers and backfills are included. The experience from the comprehensive international Stripa Project, concerning both systematic material investigations in the laboratory and the full-scale field experiments, has contributed significantly to this report. However, similar and additional information gained from later work in SKB's Aespoe Hard Rock Laboratory and from NAGRA and also from other waste-isolation projects have helped to make this document of assumed international interest