Ok so I'm reading this list and nodding along, then I see multiple EGG books and I start to get worried, and then we have... an outlier, an interloper. Just as I feared.
A book I do not believe the person who made this list has read (or not in the last 30 years).
A book I do not believe anyone should ever read, unless they want to get quite angry or need to do research on really badly-written DM-related books.
A book that is at odds with probably every other book on this list.
Role-Playing Mastery by Gary Gygax (1987)
I can believe maybe whoever wrote this list flicked through it, or looked at the table of contents, or even read the beginning of the book (where it initially seems merely dated, with claims like RPGs "necessarily" have "lengthy and complex" rules), but once you get into the nitty-gritty of it, it contains just absolutely toxic-waste grade terrible advice of the "purely adversarial playing and DMing" school of thought. Anyone who reads that and follows the advice will become a worse DM, a worse player, a worse human being. This is a book so profoundly bad that even Gary Gygax himself, a very flawed human being, disavowed the advice in it and said he didn't follow the advice given even at the time he wrote it. It's book bad enough that when I read it, aged all of 12 years old, I knew even from my limited DMing experience, that it was absolute rubbish, advice-wise. I remember being tempted to just leave it at the doctor's office where it finally broke me when I was reading it (literally so vivid is my memory of "this is godawful" that I'm 44 and I can remember where I was sitting when I felt it lol).
What's particularly odd is that there is an extremely excellent (far shorter) book on the same subject, which, at least for less-experienced DMs (which Role-Player Mastery is targeted at), covers the same ground, was written decades later, and is by another author on the list - Robin D. Laws - Robin's Laws of Good Game Mastering. It's only 33 pages and it's only good advice.
To be clear there's basically nothing about actual role-playing in "Role-Playing Mastery". That is not the subject of the book lol.
(I believe I have been, as the kids used to say, "triggered" lol)