This text, describes the origin and formation of lakes in order to give context to the question of how lacustrine deposits form. It explains the process of sedimentation in lakes and the chemistry of those deposits and describes how the age of lake deposits is determined. Additionally, the author shows how different groups of fossils are used in interpreting the paleontological record of lakes. In order to illustrate the more synthetic approaches to interpreting the history of lakes, he also discusses such special topics as lake-level history, lake evolution, and the impact of environmental change on lakes.