We are said to live in a “post-truth” era in which “fake news” has replaced real information, denial has compromised science, and the ontology of knowledge and truth has taken on a relativist element. I argue that to defend evidence-based reasoning and knowledge against those attacks, we must understand the strategies by which the post-truth world is driven forward. I depart from the premise that the post-truth era did not arise spontaneously but is the result of a highly effective political movement that deploys a large number of rhetorical strategies. I focus on three strategies: The deployment of conspiracy theories, the use of “micro-targeting” and “bots” online, and agenda-setting by attentional diversion. I present evidence for the existence of each strategy and its impact, and how it might be countered.