There have been a few people who have asked about starting Traveller. This needs something to be asked of them before answering properly: do they mean Traveller-the-setting or Traveller-the-rules.

Traveller-the-Setting

Traveller-the-setting is something that is dealt with in the mainline Traveller editions, starting from a loosely sketched out one in 1977’s Little Black Books and running through to Mongoose’s recent second edition revised. This provides increading details about Charted Space, the Official Traveller Universe (or Original Traveller Universe). There are of course a few digressions on the way, such as GURPS Traveller being an alternate timeline, GURPS Interstellar Wars being a jump back to the early part of the setting, Traveller 4 which is set around the start of the Third Imperium, T20 which is about 200 years before the the original (and current Mongoose) edition. Most of the official Traveller material is set in around 1110, give or take a few years, with earlier editions from Game Designers Workshop pushing that timeline forward through to around 1248. Mongoose has come back to the 1110s for their own published campaigns.

In theory, Traveller-the-setting can be played using whatever ruleset one wants (and officially there have been rules using 2d6, d20, GURPS (3e and 4e), Hero, a roll-under dice pool…) but most players likely use one of the aforementioned official versions. Of course, nothing is stopping you from using something else, if you want to go to the trouble of figuring out how it all works in FATE, BRP or whatever tickles your fancy. In this case, you probably just want to trawl through the Traveller wiki to get some lore, or mine the various official books that are available (of which GURPS provides some of the best). If you are contemplating this, you are largely on your own, so good luck, and blog about what you have done and how!

Traveller-the-Rules

The second option is to focus on Traveller-the-Rules, which have had a more confusing journey. Broadly, there are the main through-line of rulesets (Classic, MegaTraveller, Mongoose 1e, Mongoose 2e: 2d6-based, roll high) and everything else (Traveller d20, T4 and T5’s roll-under dice pools, GURPS, Hero, The New Era’s d20 roll-under thing). In general, the “everything else” section are already dealt with: use one of those if you like them and then build whatever setting you wish around those.

The main through-line of 2d6 roll high has seen a few major editions, but the most important for publishing one’s own take on them is Mongoose Traveller first edition.

Again, if you want to play in the OTU with an official ruleset, pick one of the above (most folks are likely either sticking with CT or the latest Mongoose edition).

All of these rulesets have procedures for making new sectors and systems and so on, so it would be pretty straightforward to makes one’s own setting using those rules. However, there is another option, if one is looking for something different:

The Cepheus Constellation

Mongoose 1e had an Open Game Licensed System Resource Document released. If that is gibberish, the basic idea is that the core rules and tables were made available for people to use verbatim for their own creative projects and to make their own modifications of.

Jason Kemp then extended that SRD and cleaned it up a bit to make the Cepheus SRD: https://www.orffenspace.com/cepheus-srd/

The Cepheus SRD was then used as the basis for a number of games, some (many?) of which are detailed below. Criteria for inclusion is broadly my being aware of the book and my having a copy, so if I missed something, let me know (ideally with a copy for me to look over and include). This article has also been kept to core books, not additional supplements that are standalone and add magic or new ships or similar things: ideally you grab the single book listed below and you have a complete ruleset to use. In addition, to be clear, I am not trying to review these books in a sense of which are better or worse than others per se, so much as provide a concise place to see some points of difference between what may often seem like very similar offerings (not helped by many using “Cepheus” somewhere in the name).

These rulesets (almost) all have the basic mechanic of rolling 2d6 + skill >= 8 to succeed on normal tasks. Some will add characteristics in some way as well. Difficulty is often done by either adding Dice Modifiers (negative DMs will lower the number on the dice) or vary the target number.

Science Fiction Hacks

Unsurprisingly, there are a great number of SF hacks of the base SRD.

Fantasy Hacks

There are a few fantasy hacks as well. These usually modify the careers and skills to be more suitable for lower tech assumptions. Often some sort of magic is added (and often it is just standard psionics with some new names…).

Other Hacks

Some authors like the basic 2d6 engine, so there are a handful of hacks for other times and places. This list is mostly limited to ones that are from the publishers above, unless they are listed as core rules using “Traveller” on DTRPG as well. These are often historical in nature, but not exclusively so. This section is most likely for me to have missed something, so reach out and I can try and add it.

Suggestions

While the above is fairly objective, just detailing the differences between different things. The following are more subjective, although still not actual reviews. I fully expect that my opinions will not match everyone (anyone?) else’s, but I have still tried to highlight the things that I actually like more than things I dislike or am ambivalent about.

Science Fiction Suggestions

For a complete ruleset, it is difficult to avoid the appeal of the gratis Cepheus Light. Should you be willing to handle a very stripped down thing, then Cepheus Quantum will cover the basics of character creation and personal things, if nothing for the wider setting.

If you are looking to emulate Classic Traveller specifically, none of these options are a direct match. Zozer’s Retro Sci-Fi Rules is probably the closest, but still not a purely drop-in replacement due to changes in things like chargen as well as the skills and how they are used. If you want to play Classic Traveller, for now you still need to just get Classic Traveller.

Clement Sector is probably the most fleshed out setting on this list, with a large number of ships, colonies, different types of campaign and so on detailed in various supplements. Hostile also has a fairly extensive catalogue of additional material (with much of the mechanical parts of that have been incorporated into Cepheus Universal). Faster Than Light: Nomad has had a few specific supplements that are worth looking at (in particular, Retro Rockets is a fun 1950s pulp setting). Cepheus Deluxe supplements mostly expand on the Terra Arisen setting.

If you wish to play Traveller-the-Setting, then most of these will be serviceable, although the changes to FTL travel in Clement Sector and Hostile are reasonably important, so one might want to use something else for those rules. Most of the others can serve well enough, although one would likely need to remake the various iconic OTU aliens in some way.

Fantasy Suggestions

Some subjective thoughts on these:

• Voyager complicates character generation just a hair too much by having many careers give an almost unique ability. Dropping the abilities, I think that you would get some interesting characters, and some of the generators are worth using, but overall, I am not convinced that the general setting and the rules are something that I want to bother with. I am also not overly enamoured with skill rolls being a battle for narrative control, but that is easy to ignore.
• Worlds Apart is available gratis without art and is only 100 pages, but will need fleshing out with monsters, detailed environmental and overland travelling rules and similar things if the goal is to emulate a D&D-shaped experience.
• Barbaric and Sword of Cepheus are both aiming at a sword and sorcery setting. If you prefer Cepheus Quantum, then Barbaric might appeal more than Sword of Cepheus, but otherwise the latter has more stuff in it.
• A Realm Unbounded does not really appeal to me, since it is not really doing anything dramtically different enough to give it enough juice from the squeeze.

Other Suggestions

Not too many suggestions here, since most of these are unique offerings within the broad Cepheus constellation, so if you want cowboys (for example) then unless you make your own thing, you just grab Rider. That said, the hacking rules from Zaibatsu use cards and are very elegant and worth grabbing.

Conclusion

Anyway, hopefully the above tables clear up some of the potential confusion in navigating the Cepheus constellation.