Collections of this sort are a regular publication feature of the Laboratory of Mathemati­ cal Geology of the Order of Lenin V. A. Steklov Mathematical Institute of the Academy of Sci­ ences of the USSR. In the future it is intended that further collections and monographs reflect­ ing the activity of the Laboratory be issued. In this present collection, in addition to workers of the Laboratory of Mathematical Geology, specialists of both Russia and many foreign countries participated. This has permit­ ted us to display the general level of mathematization of geology in 1966. In order to enhance the overall view, the editors have included a section "Chronicle and Bibliography" in which information is given on the most important actions relating to mathematization of geology taking place in 1965 and the first half of 1966, and which includes a bibliography on two-dimensional regressions having great practical value in geology but little known to us in the Soviet Union.