The central problem addressed is how humans achieve comprehension when spoken words inherently under-encode meaning and context allows for multiple interpretations. Wilson and Sperber propose that comprehension is an inferential process driven by specific expectations of relevance. The book explores the relationship between linguistically encoded meanings and the thoughts humans can entertain and convey, analyzing various forms of meaning including literal, approximate, metaphorical, and ironic. It further investigates whether the ability to understand speakers' meanings is linked to a broader human capacity for understanding other minds and how these abilities develop and interact throughout evolution and cognitive development.

This work is a significant contribution to relevance theory, offering a detailed exploration of how meaning is conveyed and understood through inference and expectations of relevance. It is recognized for its rigorous analysis of linguistic meaning, its philosophical depth, and its interdisciplinary approach, drawing connections across linguistics, cognitive science, and philosophy. The book is considered essential reading for scholars and students in these fields seeking to understand the nuances of communication and cognition.