Blue Book, Cover to Cover (Part XVI)

Holmes includes a section entitled "Dungeon Mastering as a Fine Art," in which he briefly discusses the (literally) artistic side of refereeing: making maps. He notes that

There should be several levels and each level should have access above and below and be made up of interlocking corridors, passages, stairs, closed rooms, secret doors, traps, and surprises for the unwary.

Though not a direct quote, this echoes much of the advice found in Volume 3 of OD&D. Beneath the section, there's this famous cross-section:
I can't calculate the way that this single illustration exerted an influence over my imagination. Even now, when I think of a dungeon, it's Stone Mountain that comes to mind. Also of interest is the fact that the text of the Blue Book notes that the Basic Set "includes the introductory module 'In Search of the Unknown'," even though later printings included The Keep on the Borderlands instead.

Next, Holmes provides us with a section entitled "Sample Floor Plan, Part of First Level." Before he actually gets around to showing us his sample dungeon, though, he digresses into a broad discussion of playing the game, including an example of play. Holmes reiterates OD&D by stating that "many rooms should be empty," two-thirds of them in fact. He also explains that

Traps should not be of the "Zap! You're dead!" variety but those which a character might avoid or overcome with some quick thinking and a little luck.

That single sentence alone says a great deal about the culture of play at the time, especially when combined with this one:

The possibility of "death" must be very real, but players must be able to win through luck and courage, or they will lose interest in the game and not come back.

Twice now Holmes has emphasized the importance of luck, something I too think is essential to the appeal of roleplaying games. His use of the term "courage" is intriguing. I suspect he meant "boldness" or "daring," suggesting that players ought not to be timid and paranoid and that be willing to take chances often yields positive results.

Holmes does suggest that the use of "appropriate speech" is an important part of the fun in the game, by which he clearly means "speaking in character." He also provides examples of swearing by deities, such as "Zeus, Crom, Cthulhu, or whatever," which says something about his own inspirations. Of course, he later on adds that

The imaginary universe of Dungeons & Dragons obviously lies not too far from the Middle Earth of J.R.R. Tolkien's great Lord of the Rings trilogy. The D&D universe also impinges on the fantasy worlds of Fritz Leiber, Robert E. Howard, Gardner F. Fox, classical mythology and any other source of inspiration the Dungeon Master wants to use.

In addition to the usual Mapper and Caller positions, Holmes suggests that one player "keep a 'Chronicle' of the monsters killed, treasure obtained, etc." This is the first time I've seen reference to such a role but it's possible it is mentioned elsewhere.

In his example of play, most of the dialog is between the D.M. and Caller, with an occasional interjection from another player. What's interesting is that, unlike in Moldvay, Holmes's example never refers to characters by their names, instead saying only "halfling" or "the fighter." My favorite bit from the example is the following exchange:

Caller: "Does he hear anything?"
D.M.: (Carefully rolling a secret die for end-of-turn wandering monster) "No. But the halfling guarding the door reports hearing slithering noises outside."
Player: "Hey, everybody, I hear slithering noises!"

That's pure gold right there.

As noted throughout this series, Holmes considers the role of the referee paramount, even going so far as to note that "the success of an expedition depends on the Dungeon Master and his creation, the dungeon." That's an unusual perspective but one that certainly makes sense in context -- without the DM's preparation beforehand, the game would be impossible. Holmes then ends his referee's section with the following reminder:

These rules are intended as guidelines. No two Dungeon Masters run their dungeons quite the same way, as anyone who has learned the game with one group and then transferred to another can easily attest. You are sure to encounter situations not covered by these rules. Improvise. Agree on a probability that an event will occur and convert it into a die roll -- roll the number and see what happens! The game is intended to be fun and the rules modified if the players desire. Do not hesitate to invent, create and experiment with new ideas. Imagination is the key to a good game. Enjoy!

It's almost certainly an exaggeration to call these this the best referee's advice ever given, but that shouldn't take away from the fact that it's excellent advice that I've carried with me ever since 1979 when I first read it. In particular, the notion that no one should expect any two campaigns to be the same is one I like and one that I wish had held the day within the hobby.