 C.I. Lewis was born on April 12, 1883 in Stoneham, Massachusetts and died on February 2, 1964 in Menlo Park, California. He was an undergraduate at Harvard from 1902–1906, where he was influenced principally by the pragmatist, William James, and the idealist, Josiah Royce. Royce also supervised Lewis’s 1910 Harvard Ph.D. dissertation “ The Place of Intuition in Knowledge”. While serving as Royce’s teaching assistant in logic, Lewis read Whitehead’s and Russell’s Principia Mathematica, a book he both admired and criticized. Later, while teaching at the University of California at Berkeley from 1911–1920, his principal research interests switched to logic. Lewis wrote a series of articles on symbolic logic culminating in his 1918 monograph A Survey of Symbolic Logic (SSL) (Lewis 1918) in which he both surveyed developments in symbolic logic from Leibniz up to his own day and presented his own modal system of strict implication. However, in response to criticism of his account of strict implication, Lewis deleted these sections from reprints of SSL and revised his treatment of their topics for his co-authored 1932 book Symbolic Logic (SL) (Lewis and Langford 1932) — “the first comprehensive treatment of systems of strict implication (or indeed of systems of modal logic at all)”, according to Hughes and Cresswell (1968, 216). 