 One of Grice's two most influential contributions to the study of language and communication is his theory of meaning, which he began to develop in his article "Meaning", written in 1948 but published only in 1957 at the prodding of his colleague, P. F. Strawson.Grice further developed his theory of meaning in the fifth and sixth of his William James lectures on "Logic and Conversation", delivered at Harvard in 1967.These two lectures were initially published as "Utterer's Meaning and Intentions" in 1969 and "Utterer's Meaning, Sentence Meaning, and Word Meaning" in 1968, and were later collected with the other lectures as the first section of "Studies in the Way of Words" in 1989.