Brook Taylor, Methodus incrementorum directa & inversa (London, 1715).
One of the leading English mathematicians of his age, Brook Taylor was on the panel that adjudicated between Isaac Newton and Gottfried Leibniz as to who had invented infinitessimal calculus (1712). He got his doctorate the year before he published this work. In it he established the branch of mathematics now known as the calculus of finite differences, and first published his famous theorem, although the full importance of the latter was not grasped until over fifty years later by Lagrange who proclaimed it the principal foundation of differential calculus.
The copy held in St John's was the gift of Sir Joseph Larmor.