This open access book responds to the emerging cybersecurity challenges by introducing a novel defensive paradigm: Safeguard Defense Mode (SDM). Developed through years of operational experience and cybersecurity drills, SDM is implemented via the Four-Honey System based on Software-Defined Deception Defense (H4SD3). This framework emphasizes early-stage APT detection, particularly during the reconnaissance phase, and shifts cybersecurity strategy from passive response to proactive guardianship. Key components of this book include: • Honeypoint: Lightweight threat detection using network and system tripwires • Honeyproxy: Traffic monitoring and anomaly detection gateway • Honeytrace: Attacker tracking and deterrence device • Honeycenter: Centralized decision and control hub • Software-Defined Deceptive Defense: A new concept for countering advanced threats • Deployment Cases: Insights from major events such as the Winter Olympics 2022, Asian Games 2023, Asian Winter Games 2025, and the Canton Fair (2016–2025) Designed for engineers, managers, researchers, and students in cybersecurity, this book presents technical solutions in an accessible format, using examples and metaphors to clarify complex ideas. While no prior expertise is required, a basic understanding of cybersecurity will enhance the reading experience.