l am pretty sure he talks about pre-online times (which were also largely pre-home-console times).
The instruction manual of my first bought game, a flight simulator on the Atari ST, was basically a printed pilot crash course.
I also had some thick copied instruction folders from the more... unconventional acquired games, often because the copy protection was like: "Enter the 5th word of the 13th line on page 54!".
Mine was the first Falcon game!
Also, my first Linux distro in 1997 came on CD and had a nice Linux introduction book l still used as a quick reference years after l had moved on to newer releases.