nginx-admins-handbook is a practical, in-depth guide for configuring, securing, and operating NGINX across real-world deployments. It distills years of research, notes, and field experience into a single handbook that complements the official docs with concrete rules, explanations, and curated external references. The handbook spans fundamentals and advanced topics alike, from HTTP and SSL/TLS basics to reverse proxy patterns, performance tuning, debugging workflows, and hardening strategies. A centerpiece is its prioritized checklist of 79 rules, grouped by criticality, helping readers focus on what most impacts security, reliability, and speed. Instead of copy-paste snippets in isolation, it emphasizes understanding trade-offs, avoiding common pitfalls, and balancing security with usability. Designed for system administrators and web application engineers, it aims to be a living companion that encourages experimentation, measurement, and continuous improvement of NGINX configurations