Introduction : war games redux? -- The nature of the challenge -- What exactly do we mean by cyber? -- How and why are nuclear systems vulnerable or at risk? -- What might hackers do to nuclear systems? -- Stealing nuclear secrets -- Could cyber-attacks lead to nuclear use or stop nuclear systems from working? -- The cyber-nuclear nexus at the strategic level -- Nuclear weapons, attribution and cyber deterrence -- Nuclear stability, crisis management, and a cyber-nuclear security dilemma -- Challenges for our cyber-nuclear future -- Nuclear weapons modernisation and the future computerised global nuclear environment -- Conclusion : managing our cyber-nuclear future.