In an era of fractured geopolitics and AI-driven acceleration, Digital Sovereignty: The Power to Decide addresses a critical question facing leaders: will you decide your organization's digital future, or will it be decided for you? Sovereignty in a digital world is something you build to your design or lose by default. However, it is a myth that one can achieve sovereignty through isolation. This book argues that, in an interconnected world, protecting your interests and staying connected are the same strategic challenge. Written by the team that built the UK Government Digital Service, this book is grounded in experience - from high-stakes contract renewals to untangling IT failures. While much of the digital sovereignty debate focuses on geopolitics and abstract policy, the approach here is practical. This is a book designed to help leaders to do, not just think. Through real-world case studies and scenarios, the authors explore how organizational inertia and vendor lock-in can gradually erode institutional agency in governments, corporates and other institutions. Regaining digital sovereignty is not about trying to bring everything in-house; it is about building the ability to make deliberate choices and the capacity to execute them. Digital Sovereignty goes beyond describing the risks of dependency to providing a practical framework for reading a situation, choosing well and making investments that last. This book is written for the leader who is ready to stop kicking the can down the road and start choosing their future.