When asked how he formulated his ideas on universal gravitation, Isaac Newton simply replied: ‘By thinking on it continually’. On an entirely different occasion, when the Marquis de l’Hospital first perused of a copy of Newton’s ‘Principia’, he expressed his astonishment at its remarkable contents by asking: ‘Does Newton eat and drink? Is he like other men?’

Both anecdotes support the belief that Newton was, indeed, ‘never at rest’. In fact, he worked obsessively on any topic that happened to grip his imagination — and he did so by forgoing friendships and more general social intercourse. Indeed, he is described in this book as a ‘solitary scholar in search of truth’. Not unfairly, he is also portrayed as a ‘man of no little petulance and paranoia’. And such traits were all too obvious in the scholarly disputes that pervaded much of his long working life.

Newton’s intellectual pursuits were not solely scientific, and the greater portion of his life was spent on the study of alchemy, theology and comparatively mundane activities, such as the management of his estate. He was also Master of the Royal Mint, a Member of Parliament and a political in-fighter on behalf of Cambridge University. Much of his time and energy was spent in written argument with Leibniz, Robert Hooke and Flamsteed. Consequently, it is estimated that only ten of Newton’s 83 years were spent on the studies from which his fame emanates (mathematics, celestial mechanics and optics).

Such are the themes of this long and very detailed biography by Richard Westfall. It has been previously reviewed in a wide range of journals, and it was the winner of the 1982 Leo Gershoy Award of the American Historical Association. Over 900 pages in length, it is now regarded as the definitive biography of the man who revolutionized 18^{th} century scientific thinking.

Notwithstanding such general acclaim, various criticisms were made with respect to Westfall’s accounts of Newton’s mathematical work. For example, it was pointed out that he had failed to distinguish between the notion of indivisibles, as used by John Wallis, and the infinitesimals employed by Isaac Newton. In the preface to this subsequent paperback edition, Westfall claims self-exoneration by saying that he didn’t regard himself as a mathematical historian and that readers should bear this in mind when reading his accounts of Newton’s mathematical achievements

Nonetheless, such criticisms don’t detract from the fact that this book is a remarkable feat of biographical scholarship. In truth, it’s hard to imagine that Westfall has overlooked any significant information about Newton’s life and times. Throughout the book, there are fascinating revelations about Newton’s wide-ranging ideas and his all too often acrimonious personal interactions. But one has to concentrate long and hard to avoid getting lost among the vast amount of detail contained within this mammoth work (painstaking research is one thing, but the limited concentration span of septuagenarians is another!).

In terms of scientific ideas, I learned a tremendous amount by reading Richard Westfall’s book. For one thing, Newton’s interests were not compartmentalised, because ideas from one field often led to innovations in another. His ideas on theology, for example, contained the notion of God’s omnipresence, which had to be reconciled with his concept of an all-pervading ether that facilitated bodily motion. Again, his work in alchemy led to the controversial notion of ‘action at a distance’, which, of course, is the principle behind universal gravitation. And Newton’s work on optics concluded with the remarkable mathematical paper ‘On the Genesis of Curves by Shadows’. In this paper, he showed that any one of 72 cubic curves is projectively equivalent to one of five divergent cubical parabolas — truly the first great result in the field of algebraic geometry.

In short, Westfall provides a good overview of Newton’s scientific output, and the circumstances of its creation. But he really intended this work to be a scientific biography — as opposed to a thorough presentation of his subject’s achievements in optics, mathematics and celestial mechanics. Those seeking a more detailed account of Newton’s mathematical works (for example) should refer to other sources. Consequently, although I hesitate to recommend this book as an introduction to the life and work of Isaac Newton, it should certainly occupy a place on the shelf of every university and college library. It will also serve as a major reference work for those with an interest in the history of science and mathematics.

Peter Ruane spent his working years mainly on the training of teachers at the primary and secondary school levels.