Talk That Counts is a sociolinguistic study of variation in discourse employing quantitative methods to explore age, gender, and social class differences in the use of features such as you know, I mean, adverbs, and pronouns. Unlike many studies of discourse variation that focus on a single social factor, Talk That Counts examines age, gender, and social class differences in a gender-balanced sample of middle-class and working-class adolescents and adults, recorded under the same conditions. Differences between adults and adolescents provided the greatest number of statistically significant results, followed by differences between males and females. The smallest number of statistically significant differences were related to social class. The range of variation underlines the need to look at more than a single extra-linguistic variable when examining discourse. It also shows the dangers of generalizing about social class, for example, on the basis of a limited sample (e.g., adolescent boys). In Talk That Counts, distinguished sociolinguist Ronald Macaulay presents an important new approach to the sociolinguistic investigation of discourse variation.