The ABCs of Cybersecurity is a comprehensive glossary designed to help both beginners and cybersecurity professionals navigate the complex world of cybersecurity. It features easy-to-understand definitions of key concepts, ranging from Active Defense to Zero Trust, and offers practical examples that illustrate their real-world applications. This guide breaks down critical terms in a way that builds a strong foundation for defending against cyber threats. Created by SANS Senior Instructor and author Keith Palmgren, this resource complements the curriculum taught in SEC301 Introduction to Cyber Security.