Within very recent time, when investigating the allowing one to explain possible transformations according to variations in different characteristics physicochemical conditions under which sedimen­ tary rocks formed, geologists were satisfied with of the environment. logical premises prompted by sound judgment. The present book is written within the indicat­ ed framework. I am pleased that this book, in which Recognizing the great role of this factor in develop­ ment of the science, it is still necessary to keep in the graphical method is used and popularized, has mind that sound judgment based on impressions and been translated into English. subjective experience of the observer does not al­ In giving a physicochemical evaluation of ways bring us to an understanding of objective existing methods for determining the oxidation­ reduction conditions under which sedimentary rocks reality. Probably greater success in explaining the form, I have tried to present the material in such a way that the warning against too formal an applica­ physicochemical features of the environment in which sediments accumulate may be achieved by tion of thermodynamics is obvious.