This article provides a comprehensive analysis of the threat that quantum computing poses to current cryptographic methods and outlines strategies for transitioning to post-quantum cryptography (PQC). It discusses the vulnerabilities of existing algorithms like RSA and ECC to Shor's algorithm, the impact of Grover's algorithm on symmetric cryptography, and the various types of post-quantum cryptographic solutions (lattice-based, code-based, hash-based, and isogeny-based). The document also addresses the timeline for the emergence of cryptographically relevant quantum computers, the potential costs and impacts of transitioning to PQC, and provides a step-by-step roadmap for organizations to achieve quantum resilience. It emphasizes the urgency of addressing the "harvest now, decrypt later" threat and recommends interim measures to protect data during the transition period.