The fundamental task of a general-purpose dictionary is to identify the words of a language, describe their actual use in speech and writing, and report what use shows about meanings. Supplementary—and controversial—tasks include describing social attitudes toward disputed usages and prescribing ‘correct’ usage. Dictionaries differ in the degree to which they honour the supplementary tasks. Some limit descriptions of status to labels attached to particular words or senses; others offer expansive guidance in usage notes appended to dictionary entries. Usage notes themselves differ—some implicitly prescribing as well as describing usage, others restricted to description of attitudes. This chapter explores the history of attempts to strike an acceptable balance between descriptive and prescriptive approaches to usage in select twentieth-century and twenty-first-century monolingual general-purpose English dictionaries, chiefly those of American Heritage, Merriam-Webster, and Oxford University Press.