In The Geopolitics of Cyberspace: A Diplomatic Perspective, Riordan explores the extent to which the key concepts of classical and critical Geopolitics can be applied to cyberspace, and how they might explain the behaviour of key state and non-state actors. Case studies seek to apply both kinds of geopolitical analysis to the US, Russia, China, the EU and internet companies, discussing what it can tell us about their past and future behaviour. Riordan then explores the implications for both the theory and, especially, the practice of diplomacy in relationship to cyberspace. He argues that foreign ministries and diplomatic services need to reform both their culture and structures to engage successfully with the challenges posed by cyberspace. Underlying the article is an attempt to rescue both diplomacy and geopolitics from popular usages that risk emptying both concepts of meaning.