Relevance theory, founded by Dan Sperber and Deirdre Wilson, was launched by their Relevance: Communication and Cognition. A stimulus will achieve relevance, to a varying degree, if it has or seems to have positive cognitive effects on them, and if the cognitive effort they must expend to derive those effects is not too great to be worthwhile. This chapter explores relevance through one major early modern work that was indebted to and influenced by commonplace books, Michel de Montaigne's Essais. Montaigne claims that his comments in the Essais on the matter or material that he proffers anecdote, example, and citation of ancient and other opinion sometimes exploit that matter in a way that is predictably relevant to his current argument, exemplifying, authorizing, or adorning it. Unlike genetic criticism or reception history, which focus on what from a holistic point of view are just the first and last stages of the literary communication circuit, relevance theory can embrace all stages.