Relativist and constructivist conceptions of truth and knowledge have become orthodoxy in vast stretches of the academic world in recent times. In his long-awaited first book, Paul Boghossian critically examines such views and exposes their fundamental flaws. Boghossian focuses on three different ways of reading the claim that knowledge is socially constructed - one as a thesis about truth and two about justification. And he rejects all three. The intuitive, common-sense view is that there is a way the world is that is independent of human opinion; and that we are capable of arriving at beliefs about how it is that are objectively reasonable, binding on anyone capable of appreciating the relevant evidence regardless of their social or cultural perspective. Difficult as these notions may be, it is a mistake to think that philosophy has uncovered powerful reasons for rejecting them. This short, lucid, witty book shows that philosophy provides rock-solid support for common sense against the relativists. It will prove provocative reading throughout the discipline and beyond.