Pierre-Simon Laplace was among the most influential scientists in history. Often referred to as the lawgiver of French science, he is known for his technical contributions to exact science, for the philosophical point of view he developed in the presentation of his work, and for the leading part he took in forming the modern discipline of mathematical physics. His two most famous treatises were the five-volume Traite de mecanique celeste (1799-1825) and Theorie analytique des probabilites (1812). In the former, he demonstrated mathematically the stability of the solar system in accordance with the universal Newtonian law of gravity. In the latter, he developed probability from a set of miscellaneous problems concerning games, averages, mortality, and insurance risks. These estimates of error and statistical inferences could be applied to social, medical, and legal matters, as well as to the physical sciences. This book traces the development of Laplace's research program and of his participation in the Academy of Science during the last decades of the Old Regime into the early years of the French Revolution.