This textbook on stratigraphy takes the student from the basic tools used by geologists to reconstruct Earth history, through to the pattern of global environmental change which has taken place since the formation of the Earth some 4,600 million years ago. The first section examines the methods used to establish, date and interpret sequences of rocks as the products of a series of events in the Earth's history. The second section presents the results obtained to show the way in which the Earth's global environment has changed through geological time.