How can we engage in a market relationship when the quality of the goods we want to acquire is unknown, invisible, or uncertain? For market exchange to be possible, purchasers and suppliers of goods must be able to assess the quality of a product in relation to other products. Only by recognizing qualities and perceiving quality differences can purchasers make non-random choices, and price differences between goods be justified. "Quality" is not a natural given, but the outcome of a social process in which products become seen as possessing certain traits, and occupying a specific position in relation to other products in the product space. While we normally take the quality of goods for granted, quality at a closer look is the outcome of a highly complex process of construction involving producers, consumers, and market intermediaries engaged in judgment, evaluation, categorization, and measurement. The authors in this volume investigate the processes through which the quality of goods is established. They also investigate how product qualities are contested and how they change over time. The empirical cases discussed cover a broad range of markets in which quality is especially difficult to assess. The cases include: halal food, funeral markets, wine, labor, school choice, financial products, antiques, and counterfeit goods. The book contributes to the sociology of markets. At the same time it connects to the larger issue of the constitution of social order through cognitive processes of classification.