The article ‘A Note on Strict Implication’ was submitted for publication by C.I. Lewis and C.H. Langford but withdrawn in proof. The paper is, according to notes and letters by both Lewis and Langford, largely by Lewis. It constitutes an early attempt by Lewis to give meanings for the modal connectives using abstract objects. To be necessary, for example, is for a statement to have the same intension as a truth-functional tautology. This theory prefigures the view of Lewis's 1946 book, (...) Analysis of Knowledge and Valuation. This introduction to the article looks at the historical background of the piece in addition to its argument and examines why it was withdrawn. (shrink)