Traveller wasn't the first roleplaying game or even the first science fiction roleplaying game (that prize goes to either Empire of the Petal Throne (1975) if you count science fantasy or Metamorphosis Alpha (1976) both of which were published by TSR) but it does count as the first space opera roleplaying game, it's also the longest lived SF RPG and the most influential both on RPGs and on gaming in general.
All of which makes it deserving of a History of Science Fiction special I think.
Traveller was designed by Mark Miller and published by Games Designers Workshop in 1977. The setting and style of the game was influenced by classic science fiction authors like Isaac Asimov, Poul Anderson and Larry Niven. And that setting is certainly one of the things that sets it apart from other early science fiction RPGs.
The Dungeons & Dragons Influence
The system is not however entirely reliant on the setting. The goal (as it was common with RPGs at the time) was essentially to produce Dungeons & Dragons in space so the mechanics could be used with settings other than the Third Imperium if the games master so chose.
When you look at the original rules for Traveller it's not hard to spot the influence of D&D on the design. For a start the stats (Strength, Dexterity, Endurance, Intelligence, Education & Social Standing) fairly closely mirror the basic D&D stats) and the values were awarded using random rolling of two six sided dice. Higher scores in a stat gave an increased chance of success.
There are some significant differences too though. For example rather than simply choosing a character class, the players generate a lifepath for their character through choices and dice rolls. The result of that establishes what skills the character has. Rather uniquely it was possible for characters do die during the generation process.
Skills were another element that distinguished Traveller from D&D (which had none at all in its earliest incarnations)
The Third Imperium
The rules, however, were not what made Traveller successful. While the original game was published without any setting information GDW supported the game with a series of supplements set in Charted Space, also known as the Third Imperium after the dominant political structure in that part of space.
The Imperium was broadly speaking a feudal structure where local nobility exerted immense control over their territory. This of course made it perfect material for local adventures.
Unique, however, there was a larger structure to the universe that GDW was building. In their magazine and their supplements they gradually moved the time frame forward and certain events played out. This gave the campaign world the feeling of being a living, breathing thing. While detailed worlds did exist even back then for RPGs, this sort of story progression was unusual.
While never quite rivaling Dungeons & Dragons, Traveller became extremely popular and in essence defined what a science fiction RPG should be for at least a decade.
Mega Traveller, The Shattered Imperium and Beyond
However, the RPG industry is an unforgiving place and while fantasy now is remarkably similar to fantasy of thirty plus years ago, tastes in science fiction have changed more substantially.
In the 80s MegaTraveller was released in an effort to update both the rules and setting. Unfortunately a lot of errors in the printing created problems understanding the rules and the radical change to the status quo of the setting met a mixed reception.
Further editions only exacerbated the situation and when Game Designers Workshop went out of business and the rights reverted to Mark Miller it was hoped that he could bring a singular vision back to the game. The end result was unfortunately a series of licensed versions that did not last very long and only added to the confusion.
Meanwhile other RPG systems like Cyberpunk 2020 free of any historical baggage were able to capitalize on modern SF tastes and combine that with a modern RPG rule system. Traveller became a niche game in a niche hobby.
Most recently Mark Miller released a 5th edition of his RPG using Kickstarter for funding, but the resulting reviews suggested that this is now a product that will appeal only to established fans of the game.
Impact Beyond RPGs
While Traveller's impact on science fiction RPGs and RPGs in general is unmistakable there has also been some bleed over into other media. In the early 80s a company called Edu-Ware released a computer RPG called Space which heavily borrowed Traveller's rule system. They were subsquently sued by Game Designers Workshop. It was another ten years before Traveller made it onto computers in legal form with two MegaTraveller titles that were met with a mixed reception.
Unquestionably Traveller's biggest influence on video games comes in the form of the early 8-bit classic space trader/space sim Elite. While one of the games creators David Braben says he never played the RPG, Ian Bell, the co-creator did and the influences are clear in the shape of some of the ships, the artwork and the nature of the game.
Traveller had more success in book form with fourteen novels having been released over the years, the most recent, Shadow of the Storm, in 2014. Also in 2014 a Kickstarter campaign gathered funds to produce a pilot for a Traveller movie. There's even a heavy metal concept album titled Traveller.