Emilie du Ch-telet was one of the most influential woman philosophers of the Enlightenment. Her writings on natural philosophy, physics, and mechanics had a decisive impact on important scientific debates of the 18th century. Particularly, she took an innovative and outstanding position in the controversy between Newton and Leibniz, one of the fundamental scientific discourses of that time.The contributions in this volume focus on this "Leibnitian turn". They analyze the nature and motivation of Emilie du Ch-telet's synthesis of Newtonian and Leibnitian philosophy. Apart from theInstitutions Physiquesthey deal with Emilie du Ch-telet's annotated translation of Isaac Newton'sPrincipia.The chapters presented here collectively demonstrate that her work was an essential contribution to the mediation between empiricist and rationalist positions in the history of science.