First off, let me say that there's nothing wrong with the Core Cosmology, or, what we used to call the Great Wheel. I mean, there are probably few people as familiar with the Great Wheel as I am -- I'm on a first-name basis with the planes of Dungeons & Dragons. Still, while working on Planescape, I would occasionally feel limited or confined by the nature of the D&D cosmology. In a way, the planes sometimes seemed too ordered, or too well defined. It might seem silly when talking about a number of infinite spaces, but every once in a while, I felt like there just wasn't enough room.

In my home campaigns (when I wasn't playing Planescape), I didn't use the Great Wheel. I figured that a lot of other people didn't, either. So when it came time to talk about the planes during the development of 3rd Edition, I think I surprised everyone by being the first and primary proponent of the idea that not every campaign needed to exist within the same cosmological setup. (As a point in my favor in the discussions, I also knew first-hand how hard it was during my tenure on Planescape development to rationalize that the worlds of Dragonlance, the Forgotten Realms, Greyhawk, Mystara, and the rest all shared the same cosmology.) I remember that meeting well. I could tell by the looks on people's faces that, when I opened my mouth to speak, they thought I'd blather on about Planescape and Sigil and how it's at the heart of everything. I hope Planescape fans don't feel betrayed when I tell you that I didn't say that at all. The cosmology set up in the original Manual of the Planes, which was based on an appendix in the 1st Edition Player's Handbook (which itself had its roots in original D&D) is great. But it's not the only way to do planes. Not by a long shot.

Thus, the 3rd Edition Manual of the Planes presents what's now called the Core Cosmology, but it also talks about creating your own cosmology. (This was one of the first 3rd Edition products in development, so the 3rd Edition team had a lot of influence over its design.) Nifty. In fact, the whole book is nifty, and -- if I do say so myself -- owes an awful lot to Planescape. In fact, about 95 percent of the details of the planes found in that book were actually taken right out of various Planescape products. But I digress.

So, when thinking more recently about other ways to do planes, I thought about what I had done in my own campaigns. The planes in my games had always been heavily influenced by the writings of Michael Moorcock. Not in their specifics (no planes ruled by Xiombarg, no vulture lions, etc.), but in the fact that the planes were like islands in an endless sea. A learned person might know a lot about the nearby islands, but nothing about those farther out. And no one had ever cataloged all of them, because the sea was truly endless. Thus, you get the best of both worlds: You can have a detailed setup of planes, so that people know about where the demons come from and where the gods live, and so on, but you can also have faraway planes where alien and unknown things come from. You can have both the known and the unknown. You can come up with any idea you want and create a plane around the concept.

Moreover, in Moorcock's books, sometimes other planes were parallel worlds, like the home of the main character but different in history or setup. And sometimes they were bizarre alien realms that bore no relationship to the "normal" world, whose laws of physics were completely different. Still, more or less, a plane was a plane was a plane. (I imagine a more ardent Moorcock fan than I would say that the more lawful a plane was, the more like a normal world it was, and thus the more chaotic it was, the more alien and strange it was. Whatever.)

The whole point is, I liked the idea of lots of different kinds of planes. Thus, I created the Countless Worlds. This is the cosmology of Beyond Countless Doorways. It's a multiversal setup that allows for anything you can imagine. To impose a small bit of order, the various planes in the Countless Worlds can be generally categorized as heavens, hells, alternate worlds, parallel worlds, elemental planes, energy planes, and alien realms.

HEAVENS AND HELLS
There is not one heaven and one hell, but many -- perhaps countless numbers of both, each individualized and separate, none forming anything resembling a cohesive whole. No lord of heaven masters all celestials and champions of goodness nor does any duke of hell rule all demons and devils. Instead, there are many such beings -- demon princes, archdevils, angelic kings, and celestial stewards -- who each rule an appropriate plane or portion of a plane.

ALTERNATE WORLDS
These worlds are not unlike the one in which most campaigns exist: lands divided by mountains and rivers and bounded by oceans, forests, and kingdoms filled with cities and towns, roads and farms. Viewed from a metagame perspective, an alternate world might seem like "somebody else's campaign world." Not all alternate worlds are that big or robust however.

PARALLEL WORLDS
In an extremely disconcerting experience, planar travelers can find their way to a plane that seems exactly like their own -- but it is not their own. Instead, differences ranging from the almost imperceptible to the wildly catastrophic show this to be an entirely different world: a parallel world.

ENERGY/ELEMENTAL PLANES
Some planes are pure energy, or nearly so. Planes of pure magical energy exist, as do planes of only positive energy and, of course, those of negative energy. Explorers have even found planes of more esoteric energies, such as pure light, absolute darkness, deadly radiations, sound, pure thought, and more.

Other planes are composed of a single element, or primarily of a single element, so much so that they are identified only for that element. These planes are usually the home of elemental creatures, from elementals themselves to genies, xorn, and far stranger creatures. While most elemental planes revolve around the four cardinal elements -- air, earth, fire, and water -- a few exemplify much stranger compositions, like bubbling ooze, magnetism, crystal, or wood.

ALIEN REALMS
Some planes defy categorization. They have little or no solid ground. Energy vortexes twist space back upon itself. Even concepts like "up" and "down" become meaningless. Each alien realm is different and unlike anything found on a traveler's home plane. They bear little or no resemblance to each other.

Time itself may flow at a different speed in an alien realm, and space and distance might work differently as well. Time to cross a given distance might be random rather than based on length or speed, or speed might be determined by state of mind, size, or knowledge rather than normal factors.

This is the cosmological breakdown I sent to my Beyond Countless Doorways coauthors. Wolfgang, Colin, and Ray each worked on Planescape with me back at TSR, and they were as eager as I was to get out there and explore the planes again.

It's not just the different kinds of planes that sets the Countless Worlds apart, however. The real heart of it all is that the planes move in a metaphysical, beyond-three-dimensional sense. They come in and out of conjunction, they weather storms, and more. I'll get into the details of that, and what it all means, next time.

DESIGN DIARY PAST ENTRIES

* Keyed Spell Items in Book of Hallowed Might II -- April 15, 2004
"Mike and I did some work recently on Book of Hallowed Might II: Portents and Visions. The Book of Eldritch/Hallowed Might series has been great to me...."

* Legacy of the Dragons: A Monstrous Challenge -- February 26, 2004
"I love new monster books so much, I pretty much never pass one up, no matter what. I wanted Legacy of the Dragons to be friendly to the folks out there who are like me."

* Legacy of the Dragons: Bestiaries I Have Known -- February 19, 2004
"My first professional game design ever was a book of monsters. Creatures and Treasures II came out in 1989 from Iron Crown Enterprises for Rolemaster..."

* Legacy of the Dragons: Context -- January 22, 2004
"Legacy of the Dragons is the product I'm working on now. Just finishing it up, actually. It's a bestiary to go along with Monte Cook's Arcana Unearthed...."

* Chaositech Playtesting -- December 11, 2003
"Chaositech is one of those products that came directly out of my campaign. The concept was not meant originally to have anything to do with a product...."

* Campaign Paradigms -- October 30, 2003
"An important thing for all DMs to keep in mind is that once a campaign is up and running, the basic flavor -- the underpinnings of the whole campaign structure -- usually should not change...."

* Developing a New Subsystem -- October 2, 2003
"Probably one of the biggest challenges that faces a designer when working on a book like Chaositech is the delicate way that you have to institute a whole new subsystem...."

* On the Horizon: Chaositech -- September 11, 2003
"If you'll indulge me, I'm going to divert the Design Diary's contents to what I'm working on now: a book called Chaositech...."

* Magic Items in The Diamond Throne -- August 28, 2003
"Magic items in Monte Cook's Arcana Unearthed and in The Diamond Throne sometimes require a little bit of thought on the DM's part. Using them isn't a problem..."

* A Look at the Land -- August 15, 2003
"This week I've prepared an excerpt from The Diamond Throne. As I've said previously, it was my design choice to spend most of the gazetteer portion of the book on the general aspects of the world..."

* Designing a World -- August 7, 2003
"I have mixed feelings about campaign settings. On one hand -- speaking as designer -- it's fun, challenging, and rewarding to create a whole world that's all your own...."

* Weapons and Armor -- July 17, 2003
"I absolutely love the introduction of exotic weapons into D&D. It's one of my favorite things about 3rd Edition. In Arcana Unearthed, I wanted to make sure that the exotic weapons were worth the feat required to use them...."

* Greenbond Notes -- June 26, 2003
"Last week's preview of the greenbond class gives a nice glimpse of a lot of Arcana Unearthed issues. First off, the greenbond is no druid...."

* Spell Templates -- June 12, 2003
"This week I thought I'd discuss an idea that I'm really very happy with. The idea is spell templates..."

* Playtesting -- June 5, 2003
"Playtesting is extremely important to me. When we developed 3rd Edition, we did more playtesting than perhaps any other RPG product, ever...."

* High Magic -- May 29, 2003
"I referred to the Diamond Throne as a high-magic setting. I should clarify..."

* The Diamond Throne -- May 23, 2003
"So it's about time I start talking about the Diamond Throne. The Diamond Throne is a campaign setting for Arcana Unearthed -- the default setting, like Greyhawk for D&D, I suppose...."

* Death's Door -- May 8 , 2003
" I like the D&D death's door rules. I like that at 0 hp, you're still up and can take a limited action, but then you exhaust yourself...."

* Hero Points -- May 1, 2003
"A roleplaying campaign can be like putting up wallpaper...."

* Truenames -- April 18, 2003
"Truenames are common in many fantasy settings. I think I first became aware of the concept in Ursula K. LeGuin's Earthsea trilogy..."

* Go, Go, Go! -- April 10, 2003
"Short entry this time. I hate spells with 1 minute/level durations...."

* Ceremony -- April 3, 2003
"I think I've already mentioned that one of the goals I set for myself with Arcana Unearthed was to make things a little less generic...."

* Things That Rules Take Away -- March 21, 2003
"There are aspects of fantasy roleplaying that rules, inadvertently, can actually take away...."

* Still Talking Classes -- March 13, 2003
"I've saved some of the best classes for last. Let's talk about the runethane, the mage blade, and the witch...."

* More Classes -- February 27, 2003
"This time, I want to tell you about some of the other classes: akashics, magisters, and greenbonds...."

* Build a Better Fighter -- February 23, 2003
"The title this week is facetious. It really should be 'build a different fighter'...."

* The Magic Balancing Act -- February 13, 2003
"In Arcana Unearthed I'm introducing a new method of magic item pricing. First, I streamlined the item creation feats..."

* More Magic -- January 23, 2003
"This week, I thought I'd talk more about the new magic system in Arcana Unearthed."

* Magic -- January 17, 2003
"As a designer, magic in Arcana Unearthed posed a huge challenge. I knew that I wanted to ditch the Vancian system...."

* Design Decisions, Part Two -- December 24, 2002
"Here's a bit more discussion of some of the general issues I faced as I began designing Arcana Unearthed...."

* Design Decisions, Part One -- December 19, 2002
"Before jumping into another big area of Arcana Unearthed's design, like classes or the magic system, I thought I'd discuss some of the general issues I faced as a designer starting the book...."

* Arcana Unearthed Races -- December 5, 2002
"I started with the races. While I knew that the game needed humans as a basis, I wanted all the other races to be new. I didn't want to just create dwarf and elf analogs with different names...."