Malicious open-source packages are an unseen but rapidly growing threat to U.S. government. A 92% spike in identified malicious packages from 2022–2024 underscores the urgency. This e-book equips mission teams to detect, prevent, and mitigate these risks by explaining the threat landscape, outlining automated protection strategies, and showing how to integrate malicious-package security into existing development workflows. A critical guide for anyone responsible for secure software delivery.