  Three factors stand in the way of giving an account of Newton's work and influence. First is the contrast between the public Newton, consisting of publications in his lifetime and in the decade or two following his death, and the private Newton, consisting of his unpublished work in math and physics, his efforts in chymistry — that is, the 17th century blend of alchemy and chemistry — and his writings in radical theology — material that has become public mostly since World War II. Only the public Newton influenced the eighteenth and early nineteenth centuries, yet any account of Newton himself confined to this material can at best be only fragmentary. Second is the contrast, often shocking, between the actual content of Newton's public writings and the positions attributed to him by others, including most importantly his popularizers.  The term “Newtonian” refers to several different intellectual strands unfolding in the eighteenth century, some of them tied more closely to Voltaire, Pemberton, and Maclaurin — or for that matter to those who saw themselves as extending his work, such as Clairaut, Euler, d'Alembert, Lagrange, and Laplace — than to Newton himself.  Third is the contrast between the enormous range of subjects to which Newton devoted his full concentration at one time or another during the 60 years of his intellectual career — mathematics, optics, mechanics, astronomy, experimental chemistry, alchemy, and theology — and the remarkably little information we have about what drove him or his sense of himself. Biographers and analysts who try to piece together a unified picture of Newton and his intellectual endeavors often end up telling us almost as much about themselves as about Newton.