Typically, D&D has had three major books necessary to play the game:
- The Player's Handbook which tells you how to play the game and make your character.
- The Dungeon Master's Guide which tells you how to run the game and make adventures.
- The Monster Manual which includes pre-made critters for your party to encounter.
Now, the first two books largely do their job to varying degrees of effectiveness.
The third book, though, could use some re-examination. I think 4e shows this relatively well. The 4e MM is a collection of monsters and statblocks, but that alone isn't enough to get someone to use a particular monster. 4e's MM is arguably the most focused collection of monsters and statblocks ever, but it's not enough. As the designers seemed to realize as time went on, DMs need more than combat stats and some perfunctory fluff to run a monster well.
So, is this just a matter of how much story material ("fluff") is included with the beastie? Do we need to return to 2e's ecologies and societies? Are a mimic's mating habits really relevant for the game? Or is it even valuable background material? Does it help a DM run a better mimic?
I think fluff for the sake of fluff doesn't quite get at it. The problem here isn't quantity, it's quality.
Not Just Combat Machines
Looking back through past MMs and comparing them to 4e's, a major difference becomes readily apparent: 4e's MM focuses exclusively on monsters you fight. Other MMs have a variety of creatures, from things you fight, to creatures you can ally with, to creatures all you need to do is dance around with, or who only exist to screw with you in some way. 3e's Angels, 2e's "Mammals," even 1e's mimics — not necessarily combat machines.
So what are they?
Really, they're mostly just interesting encounters. Like I point out elsewhere, players do more than fight, so the MMs in previous editions included interesting exploration and interaction challenges, too. From green slime to angels to animals to ear seekers, the creatures therein weren't necessarily there to last in a fair combat, they were there to be an interesting encounter.
This has repercussions for any MM: you can't just be a catalog of combat stats. You need to be a catalog of interesting encounters.
Encounters, or Adventures?
Given the ideas behind Adventure-Based Design, we see that interesting encounters are great, but not quite enough. What we need are interesting adventures.
This gives us a stronger book for newbie DMs — a better "core" book than a list of monster stats could ever really be: a book of adventures, that DMs can dismantle and reassemble however they want, a recipe book of quests and conflicts.
This doesn't quite resemble the classic Monster Manual any longer, though. Perhaps it has become a separate beast: the Adventure Guide.
What's In an Adventure Guide?
In an Adventure Guide, you get a series of entries that revolve around adventure antagonists (such as kobolds, The Forest of Mystery, and the College of Necromancy) rather than individual creatures (such as bears, mimics, and oozes). Those individual creatures may still occur, as part of the adventures that focus on the antagonists. Those adventures have maps, traps, and interactions as well — an entire spectrum of things useful at the table during an adventure with the featured antagonist.
Function Over Fluff
The "fluff" in this model is minimal, though the entry is not mostly combat stats. Mostly, the entry is an actual demonstration of how to use a given antagonist in play, with bits of rules you can take out and use in isolation, or with the other things in the entry. This is useful information for all three pillars: interaction with NPC's, exploration of the lair, and combat with the creatures that live there.
Mating habits aren't very useful. But attitudes, and traps, and allied creatures, and how they recharge when the party flees…these can be useful things in actual play.
What About My Encyclopedia?
A book like this doesn't invalidate a future encyclopedia of combat stats, but the value of such a book falls into question with things like online databases — certainly for the purposes of catalog, organization, and reference, an online database is much better than any book could ever be.
Still, an Adventure Guide can serve these purposes adequately. Assuming there's a quick-and-easy monster creation engine (a la 4e) in the DMG, and an Index in the adventure guide of various stat blocks and rules bits, folks just looking for a particular statblock can find one or make one pretty easily.
Supporting All Three Pillars…and Lazy DMs.
A book designed in this light helps support all DMs in all three pillars, as it includes traps, diseases, creatures, NPC's, and a host of things that can be removed from their entries and scattered into any DM's home game however they please.
It also supports new or lazy DMs by giving them everything they need right there on the page, rather than scattered over the 900 pages combined pages of the three core rulebooks.