Since founding at the 23rd International Geological Congress in Prague in 1968, the International Association for Mathematical Geology has organized sessions in conjunction with the Congress. The 27th IGC in Moscow was no exception and the IAMG again held sessions and assisted the Congress in organizing Section 20 -Mathematical Geology and Geological Information ( D. F. Merriam, D. A. Rodionov, and R. Sinding-Larsen, conveners). All together 128 abstracts were published in the technical proceedings. Several of the papers were published prior to the Congress, others were not available, and others deemed not appropriate for publication in this volume. This collection then contains those papers aVailable and representative of the sessions. The collection is truly international with contributions from Canada, China, France, Poland, the UK, USA, and USSR. They are representative of the state-of-the-art as of the early 1980s in a variety of fields. The application of geomathematics/geostatistics to geological problems has been hastened by the availability of computers. These papers reflect that orientation -most of the results would not have been possible without the use of computers. Most of the approaches utilize techniques readily aVailable and adapted to solving geological problems -simulation, image analysis, decision theory, fuzzy sets, etc. However, one area, that of geostatistiques which includes Kriging, has been designed especially for use by earth scientists of the French school to solve geological problems.

It has been evident for several years that a summary of where we came from, where we are, and where we are going with computer-oriented research was not only desir able but necessary. The application of computers by earth scientists is numerous and the methods have proved of val ue in problem solving as well as data processing. Many methods unknown or unavailable just a few years ago now are used routinely. An overall appraisal of the methods at this time is deemed more than appropriate. Preface to the program was stated as Computer applications in the earth sciences is the subject of this International Symposium held on campus at The University of Kansas at Lawrence on 16, 17, and 18 June 1969. The symposium, the sixth in a series, is sponsored by the Kansas Geological Survey, International As sociation for Mathematical Geology, and University Extension. Papers by leading experts in their field stress the "status-of-the-art." Speakers will discuss the use of computers in the earth sciences, past, present, and future. The meeting is planned for those not acquainted with the tremendous ad vancements made in quantitative methods in recent years and those who are interested in future pos sibilities."

Computer Simulation of Sedimentary Cover Evolution; S.E. Medvedev. Numerical Simulation of Pore Fluid Movements in the Upper Rotliegend of the North German Depression; J. Springer, G. Schwab. Modeling of Subsidence, Temperature, and Maturity in the North German Basin; A. Berthold, K. Menschner. Differential Compaction and Structural Genesis; H. Dietrich. Dissolution and Cememtation in Basin Simulation; R. Ondrak, U. Bayer. The Use of Fision Track Measurements in Basin Modeling; P.K. Jensen, et al. Mass-Balanced Reconstruction of Paleogeology; W.W. Hay, C.N. Wold. The Simulation of Large-Scale Sedimentary Structures; P.A. Dowd. A Quantitative Basin Analysis System for Petroleum Exploration; S. Cao et al. Well-Log Imaging and its Application to Geologic Interpretation; L. Huang, et al. An Integrated Approach to Basin Analysis and Mineral Exploration; D.F. Merriam, et al. 8 additional articles. Index.