At the beginning of this book, I articulated four questions about the semantics of word formation:

• The polysemy question: why are derivational affixes frequently polysemous? Do they have a unitary core of meaning, and if so, what is it?

• The multiple-affix question: why does English often have several affixes that perform the same kind of function or create the same kind of derived word?

• The zero-derivation question: how do we account for word formation in which there is semantic change without any concomitant formal change?

• The semantic mismatch question: why is the correspondence between form and meaning in word formation sometimes not one-to-one?

My goal throughout has been to begin to find answers to these questions. Doing so has necessitated developing a system of lexical semantic representation that allows us to characterize the meanings of simplex lexemes as well as affixes and complex words. In this system I have distinguished the semantic skeleton – that part of the representation that is decompositional, hierarchically arranged, and devoted to those aspects of meaning that have consequences for the syntax – from the semantic body – that part of the representation that is encyclopedic, holistic, and nondecompositional. I have motivated six semantic features [material], [dynamic], [IEPS], [Location], [B], and [CI] which allow us to distinguish major ontological categories of lexemes, as well as basic concepts of time, space, and quantity. And I have articulated a principle of co-indexation that allows parts of complex words to be integrated into single referential units.