by Gale Christianson (2005). Pithy (ca 120 pages) and worthwhile biography of Newton, arguably the greatest genius-as-scientist who ever lived. It made me appreciate the extent to which Newton was both an intuitive experimentalist and one of the most gifted mathematicians ever. Newton was only 24 when he invented calculus with fluxions – quantities with a constant rate of change. By then he had also carried out the famous prism experiments and had the first insight into universal gravitation.