Narcolepsy on page 216 — a sleep disorder where you suddenly fall asleep… — Page 459, Lesson 720

I see you've turned to the index section of the book — this is the alphabetical listing of topics and the page numbers where you'll find them. Let me walk you through what's here under the letter N and into O, so you know exactly what's covered and where to look. Starting with N: we have Naps on page 211 — that's short sleep periods, relevant to fatigue management. Narcolepsy on page 216 — a sleep disorder where you suddenly fall asleep involuntarily. Nasal Decongestants on page 113 — medications you need to know about for flying, as they can affect performance. Nervous system on page 59 — the body's control network. Neurons on page 59 — the individual nerve cells that make up the nervous system. Nicotine on page 26 — the stimulant in tobacco, relevant to human performance. NIHL on page 63 — that stands for Noise Induced Hearing Loss, a permanent hearing damage risk in aviation. Noise on page 129 — general noise exposure. Noise Induced Hearing Loss again on page 63, same as NIHL. Non-Declarative Knowledge on page 157 — that's knowledge you can't easily put into words, like how to ride a bike. Non-verbal Communications on page 258 — body language, gestures, facial expressions in crew coordination. Moving into O: Obedience on page 235 — following orders, relevant to cockpit authority gradients. Obesity on pages 99 and 47 — a health factor affecting pilot fitness. Objective Risk on page 300 — the actual measurable risk, as opposed to perceived risk. Obscuration on page 153 — something blocking your view or attention. Obsessional Disorders on page 107 — a type of mental health condition. Oculogravic Illusion on page 198 — a vestibular illusion where you misperceive the vertical due to sustained acceleration. Oculogyral Illusion on page 198 — another vestibular illusion where a turning aircraft makes you feel like you're still turning after the motion stops. Omissions on page 161 — forgetting to do something, a type of error. Open Question on page 327 and Open questions on page 255 — questioning techniques used in communication and crew resource management. Optic Nerve on page 76 — the nerve that carries visual information from the eye to the brain. Optimal Arousal Level on page 125 — the ideal state of alertness for peak performance. Organisational Stress on page 134 — stress caused by the company or work environment. Orthodox Sleep — and that entry is cut off, but it refers to non-REM sleep, which you'll find in the sleep section. This index is your roadmap through the book. When you're ready, we can jump to any of these topics and I'll teach you the material in detail.