Syntax puts our meaning ("semantics") into sentences, and phonology puts the sentences into the sounds that we hear and there must, surely, be a structure in the meaning that is expressed in the syntax and phonology. Some writers use the phrase "semantic structure", but are referring to conceptual structure; since we can express our conceptual thought in many different linguistic ways, we cannot equate conceptual and semantic structures.
The research reported in this book shows semantic structure to be in part hierarchic, fitting the syntax in which it is expressed, and partly a network, fitting the nature of the mind, from which it springs. It is complex enough to provide for the emotive and imaginative dimensions of language, and for shifts of standard meanings in context, and the "rules" that control them.
Showing the full structure of English semantics requires attention to many currently topical issues, and since the underlying theory is fresh, there are fresh implications for them. The most important of those issues is information structure, which is given full treatment, showing its overall structure, and its relation to semantics and the whole grammar of English.