In a post-factual world in which claims are often held to be true only to the extent that they partisanly confirm one’s preexisting beliefs, this book asks the following crucial questions: How can one identify the many forms of untruthfulness in discourse? How can one know when their use is ethically wrong? How can one judge untruthfulness in the messiness of situated discourse? Drawing on pragmatics, philosophy, psychology, and law, All Bullshit and Lies? develops a comprehensive framework for analyzing untruthful discourse in situated context. The TRUST (Trust-Related Untruthfulness in Situated Text) framework sees untruthfulness as encompassing not just deliberate manipulations of what you believe to be the truth (the insincerity of withholding, misleading, and lying), but also the distortions that arise pathologically from an irresponsible attitude toward the truth (dogma, distortion, and bullshit). Truth is often not “in play” (as in jokes or fiction), or concealing it can achieve a greater good (as in saving another’s face). Untruthfulness becomes unethical in discourse, though, when it unjustifiably breaches the trust an interlocutor invests in the speaker. In such cases, the speaker becomes willfully insincere or epistemically negligent and thus culpable to a greater or lesser degree. In addition to the theoretical framework, the book provides a clear, practical heuristic for analyzing discursive untruthfulness and applies it to such cases of public discourse as the Brexit “battle bus,” Trump’s tweet about voter fraud, Blair’s and Bush’s claims about weapons of mass destruction, and the multiple forms of untruthfulness associated with the Skripal poisoning case.