Designing Defensible OT Networks: Architecture Patterns for Safety and Availability explores the engineering principles and architectural strategies that protect modern industrial systems from disruption without sacrificing performance or safety. It guides readers through the full spectrum of operational technology design, from segmentation and redundancy to secure remote access, incident containment, and audit-ready governance. Blending cybersecurity, control engineering, and real-world operational insights, the book provides a framework for building resilient, traceable, and defensible OT environments that can withstand both technical failure and cyber threats while sustaining continuous, safe, and compliant operations.