I'm not going to do this kind of super-close reading all the way through. At least I don't think I am. Mostly it'll apply to passages of particular importance, that set the foundation for the rest of the work. I have a lot more to say about philosophy of gaming and principles of play than about the details of encumbrance, for instance.
That said, Chapter 1, “A World of Your Own”, opens with some fascinating stuff I do want to read closely. So here we go!
Your world is the setting for your campaign, the place where adventures happen. Even if you use an existing setting, such as the Forgotten Realms, it becomes yours as you set your adventures there, create characters to inhabit it, and make changes to it over the course of your campaign. This chapter is all about building your world and then creating a campaign to take place in it.
I like every part of that paragraph. It repeats the theme already established, and enthused about here, about how every campaign's world becomes its own in play. I continue to think this is true, and important to remind DMs of.
The first section heading is The Big Picture, and the next page or two is what really, truly sold me on 5e. What we get here is a review of the core assumptions of D&D for this edition, each with a paragraph of commentary: Gods oversee the world. Much of the world is untamed. The world is ancient. Conflict shapes the world's history. The world is magical. Here's their style:
The world is ancient. Empires rise and fall, leaving few places that have not been touched by imperial grandeur or decay. War, time, and natural forces eventually claim the mortal world, leaving it rich in places of adventure and mystery. Ancient civilizations and their knowledge survive in legends, magic items, and their ruins. Chaos and evil often follow an empire's collapse.
Matching these is a set of possibilities under the subheading It's Your World. They include: The world is a mundane place. The world is new. The world is known. Monsters are uncommon. Magic is everywhere. Gods inhabit the land, or are entirely absent. Here's the last of those:
Gods inhabit the land, or are entirely absent. What if the gods regularly walk the earth? What if the characters can challenge them and seize their power? Or what if the gods are remote, and even angles never make contact with mortals? In the Dark Sun setting, the gods are extremely distant – perhaps nonexistent – and cleric rely instead on elemental power for their magic.
This is a very confident, self-aware piece of writing. Its creators know what they want, and are aware that they're making choices from among a range of possibilities for each chosen emphasis, and are comfortable encouraging DMs to make their own choices. They keep tying various options back to existing D&D settings, too, which is good for awareness of all the various flavors of D&D as parts of a greater whole, and helpful to DMs wondering something like, “Hmm, what should I do to give my game a feeling like that?”
The expository tone and style continue to impress me, too. I'm reminded of something Justin Achilli wrote in instructions to authors for one of his Vampire: The Masquerade projects, to the effect of, “Don't make readers jump through hoops to understand what you mean. They've already proven they're cool enough by buying the book.” This is straightforward writing, which is an entirely different thing from stupid writing. Useful simplicity takes just as much work – sometimes a lot more, really – than useful complexity.
Next up will be the discussion of gods and religions, which continues the trend of most excellent utility.