The metaphor of language as glass explains vividly why the world looks different in other languages. For Deutscher, who holds a constructionist view, the world remains the same when people speaking different languages perceive it. He construes the associations between people, language, and thought as social, historical, and cultural creations. His monograph consists of two parts: “Language mirror” and “Language lens,” with a “Prologue” before and an “Epilogue” after.

In the prologue, the author introduces interesting anecdotes and evidence in order to encourage readers to critique some long-held beliefs about the language-thought-culture relationship. In the overview, he raises thought-provoking issues such as whether language reflects human nature or culture. The five chapters in Part 1 are illustrative of language functioning as a mirror of the mind. Deutscher's central argument is that the labels assigned to objects reflect cultural conventions, while everything behind those labels reflects the nature of those objects. This argument bridges the gap between culture and nature in relation to language. Starting from an analysis of color terms and humans' perception of color, the author asks why the sea has a “wine-red” color in Homer's epic. The answer, he says, is that no such color term as “blue” existed in Homer's lifetime. Ch. 2 shows that the evolution of humans' color perception is closely related to the emergence order of color terms. He contends in Ch. 3 that in the nineteenth century the failure to use specific color terms to name different shades of a color was caused by the absence of those terms, not by color blindness. The author argues in Ch. 4 that different languages have a similar pattern in expressing the color spectrum, although slight variations exist. In Ch. 5 he looks into the flaws in the well-known proposition that all languages are equally complex.

In Part 2, the author utilizes mainly reports from field research and experiment results to discuss issues concerning linguistic relativity. He contends that language may function as a lens through which we humans perceive the world. This implies that language use somewhat twists our understanding of the world, which is perceived differently by people speaking different languages. His contention is supported by the problems identified in the Sapir-Whorf hypothesis in Ch. 6. In Ch. 7, the author shows how speech habits can create habits of mind, which in turn affect orientation skills and patterns of memory. Ch. 8 cites evidence from grammatical gender to back up his claim that a gender system of language does not affect its speakers' ability to reason logically. Echoing the central topic in Part 1, the author brings back the use of color terms in Japan and Russia in his last chapter. He reaches the conclusion that it is cultural conventions rather than language proper that really count in shaping its speakers' modes of thought. In the epilogue he points out that the investigation of the impact of language on thought is just beginning to be put on a research agenda. As this impact is intangible, a lot has been left unexplored. This volume inspires readers to question, critique, and probe into the flaws in some well-accepted knowledge.