Earth is often compared to a huge house, and you and I are one of the inhabitants of this planet house. And so we need to study all its "premises": high mountains and endless plains, restless oceans, periodically active volcanoes, tongued glaciers and life-giving rivers. The encyclopedia will introduce many of the mysteries of nature that man has not yet been able to fully reveal. They exist in the deep zones of the earth's crust and bottomless spaces of the atmosphere, in the restless waters of the oceans and among numerous living organisms.