Ancient rhetoricians such as Cicero and Quintilian advised orators to apply memoria strategies to memorize their speech. Modern public-speaking textbooks recommend various rhetorical techniques to make messages memorable for audiences. However, the effect of these techniques on information retention has been sparsely studied.This dissertation investigates how rhetorical techniques in speeches can enhance information retention by the audience. Using a three-way approach, it connects rhetorical theory, advice and practice to insights from memory psychology.First, an analysis of influential English-language and Dutch-language public-speaking textbooks showed that frequently advised retention techniques are related to organization, elaboration and visualization—three encoding principles that contribute to information storage. Authors prefer the conclusion of a speech for influencing retention.Secondly, the study describes how scholars, politicians and TED speakers use organization and elaboration techniques (e.g. summaries and anecdotes) in public-speaking practice. Results indicate discrepancies with textbook advice and context-dependent technique variants.Thirdly, two experiments were performed that focused on three organization techniques applied in conclusions of informative presentations. Results show that announcing the conclusion and providing an informative summary can enhance information retention by the audience. We are one step closer to knowing what makes messages memorable.