Look at the entries here — Page 661, Lesson 790

This is the index of the book — the alphabetical list of topics and the page numbers where they appear. I want to walk you through what this tells you, because learning to read an index is part of learning to use your reference material properly. Look at the entries here. We have "Readability" on page 8, "Read Only Memory" — which we abbreviate as ROM — on page 309. "READY NAV" appears on pages 240 and 242. "Real Wander" on page 142. "Recovery Factor" on page 31. "Rectified" on page 218. "Red and Blue Poles" on page 106. "Red Radial Line" on page 45. "Reference System" on page 337. "Regional QNH" on page 64. "Remote Indicating Compass" on pages 204 and 211. "Remote Light Sensor" on page 283, and "Remote Light Sensor Unit" on page 281. "Remote Reading" on pages 26 and 27. "Remote Vertical Gyro" on page 178. Then we continue: "Frequency Modulated Continuous Wave" — abbreviated FMCW — on page 263. "Resistance Wire" on page 28. "Resolution Advisories" on page 483. "Restrictor" on page 74. "Reversion Modes" on pages 413 and 414. "Rigidity" on pages 137, 140, and 176. "RIMC" on page 204. "Ring Laser Gyros" on pages 145 and 257. "Roll and Pitch Modes" on page 372. "Roll Channel" on pages 337 and 364. "Roll Error" on page 175. And "Roll-out" — the entry is cut off there. Now, what does this index actually do for you? It's your map. When you're studying or when you need to look something up quickly, you don't read the whole book — you come here, find the term, and go straight to the page. Notice how some terms appear on multiple pages. "Remote Indicating Compass" is on 204 and 211. "Ring Laser Gyros" on 145 and 257. That tells you the topic is discussed in more than one place, often from different angles — maybe the principle in one chapter and the application in another. Also notice the cross-references between related terms. "Remote Indicating Compass" and "RIMC" — RIMC is the abbreviation for Remote Indicating Compass, and both point to page 204. So when you see an abbreviation in the index, it's telling you the full name is there too. Similarly, "Remote Light Sensor" and "Remote Light Sensor Unit" are closely related — one is the sensor itself, the other is the complete unit that houses it. One more thing to note: the page numbers tell you where in the book each topic lives. "Rectified" on page 218 — that's in the section about electrical systems, where you'd learn about converting alternating current to direct current. "Red and Blue Poles" on page 106 — that's about magnetism, the poles of a magnet. "Restrictor" on page 74 — that's in the pneumatic or instrument air section, where a restrictor limits the flow of air. So when you're using this book, the index is your first stop. Find your term, note the page, and go there. That's how you navigate a professional reference text efficiently.