This website contains an unusual paper that should interest all geotechnical engineers who would like to improve their understanding and predictions of the engineering behavior of clays. The Norwegian Geotechnical Institute (NGI) published this original paper by John H. Schmertmann in May 2012 in their Publ. No. 208 on the occasion of opening their new Schmertmann Research Laboratory wing. For the reader's convenience, the website includes copies of many of the key references cited in this paper. They should also give the reader a better understanding of the paper's history and the massive work involved in obtaining its experimental foundation.