This book gets a high rating purely for nostalgic purposes. Okay it was not the first rulebook that I ever owned, but it was certainly the most used, which sometimes puzzled me because, theoretically, you could get away with running a game without actually having this book, though having this book does make things a lot easier. Look, I'm not sure if I still have mine, but I do remember it fondly, especially the section of the spine at the top that got ripped off when the book got caught in the spokes of my bike.
Like the Player's Handbook and its weapon tables, this book had a complete list of monsters at the end, but unfortunately there were no pictures or descriptions (what's an Otyugh? All I can tell you is that it has an Armour Class of 2 and has 47 hit points). It also had a list of magic items, which does make one's job as a dungeon master easier because you do not have to go around making up things off the top of your head. However, these days (despite the fact that I don't actually have a roleplaying group at this time because all of my roleplaying friends are back in Adelaide) I am finding that I am using the Dungeon Master's Guide less and less.
I have also noted that in the second and subsequent editions the Dungeon Master's Guide became the thin book and the Player's Handbook became the thick book, but that is maybe because the creators identified that the Player's Handbook is the actual core rule book and the Dungeon Master's Guide is more like a supplement. However, I just remember that the reason that the Dungeon Master's Guide was important was because it contained a lot of stuff that related to combat, which in later editions was shifted over to the Player's Handbook.
What I remember about this book was not just the cover, but also a couple of pictures of naked and demonic people in the back. I remember back in the days when I had made friends with the son of some fundamentalist Pentecostal Christians at school and was staying at their house during exams because my parents had gone to Melbourne. I had introduced Dungeons and Dragons to my friend and his father had decided to look at it and discovered it referenced some books on witchcraft, so to him that was a big bad no-no. However, I cannot forget the look on his face when he opened up the back of the Dungeon Master's Guide to see a picture of a demon girl with her boobie showing. He just stared at it for I reckon at least a minute with this absolutely horrified look on his face.
Look to be honest, I can't really go too hard on the guy because like any loving father he was concerned for his kid and he wanted to make sure that what he got involved in was not too bad, and in particular, he didn't want his son to get involved in witchcraft. However, in all seriousness, not every Dungeons and Dragons players goes off and gets involved in witchcraft and satanism, and in fact, out of all of the Dungeons and Dragons players that I have known, very few actually did end up going down that road (it was usually the Vampire the Masquarade people who do that).
As for this book, there is one thing that I particularly loved about it, and that was the random dungeon creator. One of the things that I loved as a kid was roleplaying, and I wanted to do as much of it as possible, even when my friend wasn't able to do it (and I did find that as a teenager I did struggle to find people who would play it with me), so I ended up resorting to the random dungeon generator. Personally, I preferred mapping the dungeons, and that was why I liked the generator, but unfortunately the maps turned out to be quite chaotic. However, in the days of the old computer roleplaying games, my map making desires were somewhat fulfilled. In fact, I had whole graphbooks full of a multitude of maps that I had made from the many computer games that I had played through.
Oh, by the way, this is an otyugh.