So about OD&D presentation and style.

There long been a thread of thought that ODnD is poorly written and organized. When criticism is charitable it a result of ODnD being Gygax's first attempt at writing about a tabletop roleplaying game. When it not it because Gygax's ability as an author is also being criticized.

So this came up again in a forum that I participated one. To date the general gist of my response has been

Part of ODnD are uncleanly written but as a whole it is a work of genius and a lot of what is unclear is a result of Gygax writing for the miniature wargaming hobby as it existed in the early 70s.

But this time I got thinking that I never really dug into many of salient. So I decided this time I would look at ODnD with fresh eyes.

Men and Magic

The crucial section is on page 5 of Men & Magic titled Preparations. Here at the first Gygax summarizes and outlines everything he going to talk about.

The referee bears the entire burden here, but if care and thought are used, the reward will more than repay him. First, the referee must draw out a minimum of half a dozen maps of the levels of his “underworld,” people them with monsters of various horrid aspect, distribute treasures accordingly, and note the location of the latter two on keys, each corresponding to the appropriate level. This operation will be more fully described in the third book of these rules. When this task is completed the participants can then be allowed to make their first descent into the dungeons beneath the “huge ruined pile, a vast castle built by generations of mad wizards and insane geniuses.” Before they begin, players must decide what role they will play in the campaign, human or otherwise, fighter, cleric, or magic-user. Thereafter they will work upwards — if they survive — as they gain “experience.” First, however, it is necessary to describe fully the roles possible.

Breaking it down we see this involves

1. the referee must draw out a minimum of half a dozen maps of the levels of his “underworld,”
2. people them with monsters of various horrid aspect
3. distribute treasures accordingly
4. note the location of the latter two on keys, each corresponding to the appropriate level.
5. Explicitly states that the above will be more fully described in the third book.

Then

When this task is completed the participants can then be allowed to make their first descent into the dungeons beneath the “huge ruined pile, a vast castle built by generations of mad wizards and insane geniuses.”

But

Before they begin, players must decide what role they will play in the campaign, human or otherwise, fighter, cleric, or magic-user. Thereafter they will work upwards — if they survive — as they gain “experience.”

Then for the remainder of Men & Magic, Gygax outlines how how characters are defined, and some of what they can do or have like equipment, combat and magic.

It is in the details where writing for his expected audience of miniature wargamers is most evident. He assume that his reader has experience running or playing other miniature wargame campaigns. That they are familiar with the idea of initiative, and combat turns. That what needed to be spelled out are details to make it work at the level of the individual character. One method is the alternative system. Another is how to integrate with Chainmail, a rule system that he know many of his potential customers already have and are using to handle not only medieval melees but one and one combat as well.

Another part where his intended audience comes into play is that he doesn't offer anything like skills or general action resolution. Because he expect his audience to do the same thing they do in the miniature wargames they play. If something comes up that isn't covered by a rule or a chart, then you go back to first principles and reason it out based on how it  worked in life or in the case of fantasy in various movies and books. Something we know was common from the recent work documenting the early days of wargaming and tabletop roleplaying.

Gygax is consistent in spelling out the unique parts of the D&D rules, the parts that his fellow hobbyists would not know.

Monsters & Treasures

Then after Men & Magic, he launches into Monsters and Treasure. Which important details about two of the elements he outlined in preperation

1. Monsters
2. What treasure monsters have
3. The available treasures.

The Underworld and Wilderness Adventures

The Underworld and Wilderness Adventures is where the rest of what outlined in preparation is broken down and reinforced by examples of play.

Starting from the first page.

1. Gygax describes what he meant by levels of the "underworld" and give examples. (pg 3 to 5)
2. Offers details on distribution monsters & treasure as well other things that can go into the underworld as well as tips for keeping things fresh throughout a campaign (pg 6 to 8)
3.  Gets into the logistics of handling characters exploring the Underowold including encountering Wandering Monsters ( pg 8 to 12)
4. Give an example of play. (pg 12 to 14)
5. Presents an alternative to the Underworld the Wilderness. Like the details for an Underworld, he discusses how they are setup and the logistic of handling character exploring a wilderness.
6. The above also touts the board for Outdoor Survival game by Avalon Hill as a useful aid as well as how to use it. Which to me echos the inclusion of Chainmail in Men & Magic.
7. Then gets into constructing castle, undoubtedly something of interest to his player and his audience. (pg 20 to 21)
8. And since we are on the topic of castle, he now talks about the troops and men a character could hire as well some of the logistics of being a lord. (pg 21 to 24)
9. We now talked about castles, and troops lets talk about warfare in general including rules for stuff you wouldn't have (not found in  Chainmail) like aerial combat and naval combat. Again another example of where he writes for his audience. (pg 24 to 33)
10. And since the last thing he wrote about warfare naval combat, here are some ideas for naval adventures (page 24 to 36)

Finally wraps it up with

There are unquestionably areas which have been glossed over. While we deeply regret the necessity, space requires that we put in the essentials only, and the trimming will often have to be added by the referee and his players. We have attempted to furnish an ample framework, and building should be both easy and fun. In this light, we urge you to refrain from writing for rule interpretations or the like unless you are absolutely at a loss, for everything herein is fantastic, and the best way is to decide how you would like it to be, and then make it just that way! On the other hand, we are not loath to answer your questions, but why have us do any more of your imagining for you? Write to us and tell about your additions, ideas, and what have you. We could always do with a bit of improvement in our refereeing.

And of course

Wrapping it up
To me the above looks like a reasonable way of presenting something as novel and different as DnD was at the time. The most serious issue, that it written for the audience of miniature wargamers  resulted because the idea outlined in preparation proved so compelling that it expanded far beyond it intended audience. One that didn't share the experiences and assumptions of miniature wargamers of the early 70s. This resulted in novices to the hobby confused about aspects of ODnD.

In addition Gygax could have written a better explanation with some of the unique details of ODnD like spell memorization.

It is evident that Gygax recognized these issue given the Holmes Basic D&D was commissioned within two years of ODnD release. Then later followed up with B/X DnD, BECMI, and ADnD.

But after looking at it again I feel the presentation is solid and explains fully the most important and unique concepts that made D&D different from the miniature wargame campaigns of the day. Concepts that propelled DnD and tabletop roleplaying into their own category of gaming.