Freelance Traveller

Architect of Worlds

reviewed by Timothy Collinson

This article originally appeared in the March/April 2025 issue.

Architect of Worlds. Jon Zeigler.
Ad Astra Games https://www.adastragames.com/
192pp., softcover or PDF
US$35.00(S)20.00(P)/UK£27.50(S)15.70(P)*
* Softcover only available from Ad Astra Games website; PDF from Ad Astra Games or DriveThruRPG.

Many of us were drawn to Traveller by the world-building possibilities of the game. Rather than overwhelming referees with vast amounts of creation work and detail which might or might not get used, a simple six figure string with a few extras allowed the imagination to get fired up and the travellers moving. Brilliant, straightforward and playable. This Universal World Profile along with the Universal Personality Profile for characters were genius masterstrokes from Marc Miller. (Although watch out in early texts which occasionally use Universal Planetary Profile which can confuse things.) This world creation goes further than just a quick role-playing aid, perhaps meeting some internal need to play god, or even God, but certainly satisfying the creative urges.  In the beginning…

The basic Traveller planet generation rules – unbelievably just 12 little black book pages including a blank hex map! – were extended in Book 6: Scouts which allowed entire systems to be constructed, although with the concomitant demand on time. This then saw further expansion in Digest Group Publications’ Grand Survey and Grand Census which I remember having to order from the USA and when they arrived, put aside for several months while I finished my university degree. I knew that if I opened them the distraction would prove fatal and I might never graduate! The night of our final exam, when we were at last ‘done’ with the three-year course, my fellow-students, even as librarians, were keen to hit a local nightclub. They couldn’t quite understand why I was more interested in going back to my two new books, still unopened, which were crying out for me to build a planet or two. I managed an hour or two of trying to shout to be heard and struggling to afford vastly overpriced drinks before retiring from the field. My flatmates found me still rolling dice on their return in the small hours. Happy as Larry.

Grand Survey and Grand Census were consolidated into World Builders’ Handbook when MegaTraveller was published. Losing, I think, only the tectonic plate section. Such grand world construction wasn’t revisited until GURPS Traveller: First In written by none other than John F. Zeigler. He has also contributed to Humaniti, Nobles, Rim of Fire and Interstellar Wars if the name is sounding more than a little familiar. It’s a regret that I don’t have any of those autographed. As yet. More recently, Mongoose have published an all-new World Builder’s Handbook which goes into even more detail and dovetails neatly with their Sector Construction Guide.

All this however is not enough for the author who has clearly been very hard at work in the labour of love that is Architect of Worlds. AoW is the result of feeling the world-building rules in the core Traveller game are too simplistic, even with the Scouts expansion Zeigler notes “still, they had oversimplified some details for ease of use, and the system included a few outright errors”. This book addresses that. The author goes on: “I set out to learn how to do better. In a sense, I’ve spent most of my adult life in that quest: a study of the universe around us, for the purpose of educating my creative imagination.”

In short, this is as accurate as present-day science allows, as extensive as could reasonably be imagine for a hobby or a game, and as lovingly detailed as should satisfy the most discerning Slartibartfast intent on custom-made, luxury planet building.

To be clear from the outset, this is not Traveller specific although it can easily inform your Traveller star and planet generation. It is also not quick.  There are 31, count ’em, steps in the process. And yes, there are a few formulae. You’re going to need a calculator. However, I regard myself as somewhat mathematically challenged and even I can cope with what’s needed here. You’ll probably also need more than one sitting unless you have the Endurance of a Reginan Rhino. In return for all the effort however, you’ll produce systems and worlds that conform to our current understanding of science, provide lots of ‘rich decision making environment’ as Marc Miller might put it, and provides more than enough detail for errant explorers or scouts. It’s also worth noting that this architecture only covers the physical stats of the traditional UWP in Traveller terms; i.e., there is nothing on the society or cultures that might be found in situ. It might also be argued that this is really aimed at the gods amongst us and not the referees as in my opinion it sacrifices playability for accuracy and rather implies that you’re not going to come up with imaginative exotics that perhaps bend credibility a little, but make for fun and exciting adventure for players. Having said that, there are three pages on “unlikely worlds” which may prove of interest. As the author notes, “unlikely doesn’t mean impossible, so it might be reasonable to place such a situation in an interstellar setting as a rare case” (italics in the original). All credit to him for including this type of material although I could have used a page or three more. Readers/referees/architects will have to decide for themselves where their interests and needs lie.

Included in the author’s five-page introduction there are notes on generating random numbers, standard units and AI generated content. There is then a chapter on The Science of Star Maps which includes sections on the shape of the galaxy and our local neighbourhood. It includes building star catalogues and maps (cartesian grids, hex maps and connected-graph maps, and how that is affected by faster-than-light travel and finished up with how a designer might select the desired map volume (with information on the background population of stars, open clusters and stellar associations). Note that although standard hex maps are mentioned as an option, the author assumes you’ll include z coordinates as a number within the hex alongside the world name or label.

Once you’re past the introduction and mapping considerations, you then get the meat of the book on page 29. There are three chapters taking you through the 31 steps: Designing Star Systems, Designing Planetary Systems, and Designing World Surface Conditions; then a chapter on Special Cases in Worldbuilding. If all that sounds daunting, the author helpfully provides examples throughout as Alice and Bob build Arcadia and Beta Nine respectively. There are also ‘Modeling Notes’ which provide some commentary or offer real-world journal articles on the topic at hand. For example, in Step 4 on Star System Age there are two papers from Bovy in The Astrophysical Journal and one from Pireto in the Proceedings of the International Astronomical Union. This shows just how rooted in real and current world knowledge the book is and of course allows budding planetary architects (with access to good libraries) to do the same. It should be noted that the generation tables include d100 rolls as well as 3d6 so make sure you’ve got some ten-sided dice or a random number generator to hand. Some things I particularly like here are good, clear explanations of the different kinds of multiple star systems, the way the steps and tables take you through the history of the system so that you’re looking at protoplanetary disks, disk instability, core accretion and so on rather than merely looking at the basic data concerning a world. You’re likely to learn new things as you progress as well. Oligarchic collisions were entirely new to me and not some kind of conflict between two governments on a Balkanized world. (And despite some reading in my youth on the subject wasn’t with all of the real-world data sets that get mentioned (Bayer Designation, Flamsteed Designation, Durchmusterung Catalog, The Henry Draper Catalog, The Gliese Catalog, the Hipparchos Catalogs, the Gaia Data releases and ‘other’!). Some might feel that that all this detail will make the book difficult, I like how I feel stretched and more knowledgeable whenever I work through it. If anyone deserves to be described as having a “brain the size of a planet”, Mr Zeigler should step forward. But he carries it lightly and helps you to understand rather than just dumping you into the middle of complex concepts and processes to fend for yourself. The tag on the back cover is apposite: “We dig into the up-to-date science so you don’t have to!”

The Special Cases in Worldbuilding chapter is a lot of fun as well. Material here that of course wasn’t even known about when Traveller was first being designed and of course it’s going to be less likely in any universe modelled on the real thing, but it’s also where a lot of interest might lie for both players and their characters’ explorations. I’d bet that this is a chapter many turn to first. There are notes and details on massive main-sequence stars, neutron stars, black holes (of course!) and flare stars. The latter reminding me of a W. H. Keith adventure by that name. There’s more, however, in explanations of what might or might not be possible in the way of planetary systems, temperatures and arrangements. Rogue planets and Trojans make an appearance and there’s a page on unusual worlds such as Carbon and Chthonian planets (the latter being gas-giants which have lost their atmospheres rather than somewhere the players should fear to tread or lose their sanity). A particularly useful section here is on Alien Skies which gives you formulae and tables for working out how large things appear and how bright they look, as well as the colour of the sky.

Finally, there is a chapter on Working with Astronomical Data including two worked examples (HD 230846 and Tau Ceti) before a page or two of notes titled Science Marches On. Bringing up the rear of the book are some blank Forms: Star System Worksheet (steps 1-8), Planetary System Worksheet (steps 9-16) and World Worksheet (steps 17-31). A World Temperature Worksheet was included in the relevant step (30). There are maps, tables, diagrams and greyscale illustrations throughout. The cover is an attractive ring world with the title in a stylish font. The rear cover includes a quote on the book from C. J. Cherryh which is a great coup. It is topped by a banner shouting ‘The galaxy is yours!’ which is not untrue, if you’ve the time.

Physically the book is a rather cheap print-on-demand type of thing which is disappointing. There is some poor margin control on the back cover and last page – although the latter is advertising for the publisher’s own Squadron Strike. But the design used throughout is clear and easy to read – single column & sans serif font – and it appears that care has been taken over the formulae. The illustrations range from NASA images to system diagrams I presume the author has created and all work to suit the material at hand. Colour would have been glorious, but perhaps a PDF version can cover that. The blank forms are very nicely laid out and clear. A hardcover for the book would have been good for the bashing this kind of book is likely to get to get as you work through the pages and flip back and forth.

Would I recommend this book? Absolutely, if this is your cup of tea – or at least your dream Sunday afternoon with several cups of tea. However, for your average Referee it’s going to be far beyond what any typical Traveller or indeed other science fiction adventure requires unless you really do have scouts with enquiring minds. It’s also not possible to buy it easily outside the USA which puts a damper on purchase for many of us. I should thank my kind contact for purchasing my copy and getting it posted across the Atlantic at no small expense. If you already own the likes of DGP’s World Builders’ Handbook or Mongoose’s World Builder’s Handbook then you almost certainly have enough to be going on with. Most will probably find the Core Rulebook UWP quite sufficient, thank you. Unless, unless you must have the absolute latest real-world science, or want to lose your players in the detail (ahem, Into the Unknown, I’m looking at you), or just want the inspiration from some of the intriguing special cases. Referees will certainly want to factor in whether they’re using Mongoose rules and/or playing in the Charted Space setting or running their own universe and perhaps using a completely different rule set. If the latter, you may find Architect of Worlds more to your liking (but, see below). I’ve not regretted buying Architects of Worlds but I won’t be using it on a day-to-day basis. Not unless it’s a really rainy afternoon. Even so, expect my first full-worked up world according to the rules, sometime in, oh I don’t know, 2032. You’ll have a sense of being able to apply for a job at NASA when you’re done, but the satisfaction will be planet-sized as well. The author is to be congratulated on a tour de force that fires up the creative imagination he was questing for.

Other Similar Books

Some notes of comparison with other similar books:

World Builder’s Handbook by Geir Lanesskog.  Mongoose Publishing, 2023. 256 pages, hardcover.

This is in colour and nearly twice the size. However, it’s main advantage lies in tying in with the basic Traveller Core Rulebook planet generation. You can either start a world or a system from scratch or you can extend an already extant UWP and all the data will fit together and be presented in familiar Traveller formats. It makes a good effort at updating the science from, say, the now nigh on three decades old DGP World Builders’ Handbook with segments on stars, system age, additional atmospheres, tidally locked worlds and special circumstances etc. However, Zeigler might argue it is building on a system that is already inherently flawed. WBH [Mongoose] also has the advantage of including the population and society parts of the UWP and extending those along with the physical stats. For example city and government detailing is back. Law Levels become more granular and there’s lots of role playing opportunity added there. Detailed tech levels make a return. In addition, there are chapters on the IISS, native lifeforms, survey equipment, vehicles and robots. It’s also fun to see seismology back again after been dropped between Grand Survey and WBH [DGP].

What I have not yet attempted is to construct a system with WBH [Mongoose] and then work through AoW to adjust anything that felt ‘incorrect’.  I’ll be interested to hear if anyone tries that. Meanwhile, what might I have given to have had this volume back in my student days?!

Core Book 3: Worlds and Adventures by Marc W. Miller. Far Future Enterprises, 2019. 304 pages, hardcover (of which, the first 90 odd pages are devoted to world building and mapping).

This is of course the third volume of the mighty Traveller⁵ boxed set and shows Marc’s vision for what things could look like. It will be familiar to those who’ve lived with a Traveller for a long time although it does things in a slightly different way which may cause you trip up if not careful and requires knowing ‘other bits’ of rules to join up all the dots which can be irritating in a three-volume set. It also revises how world maps look with different maps for different sized worlds simply to keep a standard hex size which makes some maps look really awful. But there’s lots here to love and plenty you can pinch for detail where you want it even if you’re just doing basic world generation. I’m fond of the gas giant terrain, for example, which is new (and in my opinion much needed for operations in the atmospheres of those worlds) and I quite like the terrain images and symbols which get me thinking about what I’m placing on a map. I also rather like the random location on a world map, map triangle or hex if you’re tired of making it all up and just want the dice to decide. Perhaps one for the aficionado but if you’ve got it on your shelf or hard drive, you’ll find it of use.

Building Better Worlds by Andrew Gaska and Dave Semark. Free League, 2023. 295 pages, hardcover.

This is a rather different kettle of fish for the Alien Roleplaying Game and is highly recommended in its own right, although naturally it is heavily rooted in that particular universe. Even if you’re not interested in horror or the Alien universe specifically, there’s lots here to inspire and perhaps even use in Traveller with the chassis numbers filed off. There are chapters on pioneering as an introduction and then the History of Colonization, Organization (the various factions interested in exploration and development), Making Frontier Colonists – the character generation chapter, Gear and Ships and then Campaigns on the Frontier all before getting into the more world specific part of the book in Systems and Colonies which provides details of specific systems and worlds and a “redacted” chapter from the Weyland-Yutani Extrasolar Species Catalog which goes into some detail on a specific life-form and will no doubt be the first chapter many readers will turn to.  There’s also a sandbox campaign called The Lost Worlds and a large chapter called Expeditions which offers seven adventures. It’s actually only ten pages of an appendix, Building Your Own Better World, which lets you design worlds and this is all done via tables. Traveller, and other, Referees will find these helpful and inspirational but may find them too limited or limiting for the price of the book if the rest isn’t thought to be useful. Personally, I like it.

Cepheus Universal by Paul Elliott. Zozer Games, 2024. 443 pages, hardcover. (Some 33 pages devoted to world building).

This, and other Cepheus Engine instances such as Hostile or Clement Sector, all present standard Traveller world creation rules (under the open gaming licence) with which we’re all familiar. Where they don’t use very simplified systems. This volume does, however, have five pages on megastructures which may be tangentially relevant here.

Star Trek Adventures and Dune role playing games, both from Modiphius relatively recently, are terrific for their own universes, but are not so interested in actual planet construction. Disappointing but perhaps not surprising. Dune gets half a page in the section on designing a House, but it’s little more than “it’s raining on Mongo”. STA musters five pages on environments and Class D to Class Y worlds.  Which to be fair, may be all some Referees require.

World-building: a writer’s guide to constructing star systems and life-supporting planets by Stephen L. Gillet. Writer’s Digest Books, 1995. 198 pages, hardcover.

In the context of planet building, it’s probably worth mentioning this although it’s been around for a while. It’s part of a series on Science Fiction writing and while it’s not a gaming book and doesn’t provide any generation tables or rules or anything for getting your hands dirty, it does give useful background on all the elements that are useful in such projects. Whether you are running a game or endeavouring to publish your creations somewhere, this gives good advice on world-building with chapters on The Astronomical Setting, Making a Planet  and Stars and Suns and two central chapters on The Earth and The Ancient Earth which help with getting details right or thinking about what needs to change for your particular creative efforts. 

If I had a complaint about the book, it doesn’t have enough ‘alien’ world information although there is a chapter on Not as We Know It which gives some pointers – but I could have used more. It does have a five-page bibliography for those who want more detail, perhaps on geology or astronomy or general planetary science. There’s also not a lot on how to apply all this science to, say, a novel without overwhelming it or underselling it. I’d have expected more along these lines from a writer’s guide. 

It’s not a vital resource but can be helpful especially if you’re just starting out. It’s also been nicely produced with, instead of a dust-jacket, a good solid cover with image included so there’s a fair chance that any copies you can pick up after all this time will be in reasonable condition. If you want to focus on filling your hand-crafted worlds, you could consider Aliens and Alien Societies: A writer’s guide to creating extraterrestrial life-forms by Stanley Schmidt. Writer’s Digest Books, 1995. 226 pages, hardcover.