Newtonian scholarship took great leaps forward in the second half of the 20th century. The completion of critical editions of Newton's mathematical papers and of his scientific correspondence, as well as the publication of the first volume of his optical papers and of variant readings of the "Principia" in the original Latin, have made most of Newton's scientific work available for study and analysis for the first time. This has provided a better understanding of Newton's "Principia" and "Optics" especially regarding their origin and interpretation, much of which has remained obscure for several centuries. Some of the new developments and insights are presented in this volume, by several of the scholars who have made these primary sources accessible, and by others who are using them to elucidate Newton's work. Most of the papers included were presented at the "Symposium on the Foundations of Newtonian Scholarship", held at the Royal Society in London in March 1997.