Until FS2000, MS included a real manual in book form. The Official Guide Microsoft Flight Simulator Master the Experience, which retails for $19.95, is what MS doesn't provide you with any more. 😞
To make you think you were getting more for your money, they made it an unwieldy 8.5" x 10.75", with the type a bit larger than necessary and more pictures than needed.
This is not surprising, as it is published by Prima Games who probably assume a substantial number of potential purchasers lack the ability (or desire) to read.
If you are looking for technical information regarding FSX, this is definitely not the book for you.
What it does have is a fairly complete walk-through of the features of FSX, including tutorials, missions, aircraft statistics, failure settings and emergency simulation, online flying, hotkeys and more.
This book is clearly aimed at the first time or casual FS user, not the hard-core FS types.
Since I noted "Prima Official Game Guide" on the spine, "Games for Windows" and "Microsoft Game Studios" on the front cover, and "A Pilot's Guide for Gamers" on the back cover, I made sure to thoroughly wash my hands after handling the book.

Chief Captain
First Officer
You betcha, Red Rider 😉