Based on a thorough study of Newton’s extant manuscripts, this monograph will address and contextualize, inter alia, Newton’s causal realism, his views on action at a distance and space and time, the status of efficient causation in the principia, the different phases of his methodology, his treatment of force and the constituents of the physico-mathematical models in the context of book of the principia, the analytic part of the argument for universal gravitation, the meaning and significance of his regulae philosophandi, the methodological differences between his mechanical and optical work, and, finally, the interplay between Newton’s theology and his natural philosophy.