We usually understand novel sentences - e.g., this one - with little or no hesitation. How do we accomplish this? According to the received opinion, our linguistic knowledge divides into two modules - roughly, words and rules - which in turn correspond respectively to Lexical Grammar and Compositional Grammar. The present course concerns Compositional Grammar, more specifically Compositional Semantics -the study of how the meanings of compound expressions are derived from the meanings of their parts.