The first part of the ?Geology of the USSR? was published in 1985. Preparation of the second part took 8 years and was completed after the USSR ceased to exist. As such, the title of the second volume will be different but the area treated remains the same. During these years the geosciences have also continued to evolve as did the attitude of scientists involved in the process. For example, the geosyncline concept is now considered obsolete by the majority of workers. Nonetheless, the term geosyncline has been retired without creation of a new term for the initial stage of mobile belt development characterized by extension, spreading, subsidence, deep- water marine sedimentation and submarine volcanism. The terms ?fold belt? or ?orogen? are not, appropriate because not all orogens, such as the Central Asiatic Orogen, evolved from oceanic basins but from intracontinental areas instead. Due to the lack of a better designation the author has chosen to retain the terms ?geo-synclinal belt? and ?geosynclinal system?. But the use of these terms does not imply their fixist interpretation.