A silent countdown has begun. Your data may be safe today, but its secrets could be tomorrow's leverage. The most intelligent adversaries are collecting first and waiting to crack later. This book explains the quantum shift without the hype. It shows how quantum encryption and post-quantum security change priorities for governments, banks, and builders; why the cryptography race matters beyond algorithms; and how to act when timelines slip and budgets are finite. You will learn how to spot quantum supremacy timeline claims that matter, inventory fragile systems, and prepare for harvest now, decrypt later risks with cryptographic agility. For executives, security leaders, policy teams, and engineers, it offers a calm, practical lens on data security strategy that respects both uncertainty and urgency. If you need a roadmap that balances engineering realities with geopolitics and governance, this is it. From lattice-based cryptography trade-offs to US-China rivalry dynamics, from procurement to drills, you will gain a playbook for choices that age well. Clear frameworks, field-tested patterns, and a cybersecurity playbook approach help you protect what must endure while unlocking responsible innovation. No promises, just disciplined preparation.