Publisher: Mongoose Publishing
Author: Martin J. Dougherty
Illustrations: Andoni Fernandez, Shen Fei, Anderson Maia, Alvaro Nebot, and Amy Perret
Year: 2018
Genre: Science fiction roleplaying game supplement
Pages: 160 pages
MSRP: $49.99 for the hardcover or $29.99 for the PDF at DriveThruRPG
The Traveller Companion adds numerous optional rules to change the flavor of the game. There is plenty of material for both players and referees. Sadly, the art is unimaginative and lacks evocative dynamic art that would draw you into the world. The beginning of the book includes a plethora character options and new statistics that can change the genre of the game.
The new optional characteristics are Wealth, Luck, Morale, Sanity, and Social Standing. Wealth allows for an abstraction of purchasing items. This reduces bookkeeping for relatively small to moderate purchases without tracking every credit. Luck allows for a more pulp feel by increasing a character’s chance of success or decreasing an opponents chance of impacting the characters. Luck acts much like fate points or edge does in other systems by avoiding certain death or determining who gets attacked. Morale acts as a mental toughness and resistance or susceptibility to fear. It along with sanity work well for an alien horror style game where characters act less heroically and where their minds can be shattered from fear. Social standing represent the reputation and background characters have. It can change over the course of the game and maybe modified depending on where they are in the universe. It acts much like reputation in other games.
The next five chapters give several alternatives for character creation and advancement. Skill variants, maximum terms, different methods for rolling of characteristics or the ability to choose a point buy. There is the option to pick skill packages, pre-career options, and additional careers rather than rolling on the career table. Two new careers, the truther and the 
The next few chapters include alternate play styles, optional combat rules, and an expansion of environmental hazards. Some of the environmental hazards included are gravity, atmosphere and vacuum, diseases and toxins, and starvation and thirst, and temperature. There are additional rules for movement across different types of terrain and vehicle damage. Finally, there are about 28 additional creature and animal encounters.
There are a few pages of referee advice and interpreting the universal world profile (UWP), but the advice is fairly anemic. Several pages are given to using the Traveller Wiki, which seems wasted as one page recommending the wiki would be sufficient to direct the reader online to use it.
Four chapters are devoted to space travel and spaceports. These include rules for jump drives and misjumps, starport defenses and ports. Finally, these include slower than light travel both intrastellar and interstellar.
The book wraps up the rules expansions with combat and starship automation. Combat includes mine warfare, missiles and torpedoes, and antimatter weapons. The defenses include gravitic shielding for those games with a high tech level. One page is devoted to starship automation.
Players will find the first quarter of the book valuable, while referees will find a plethora of options and advice for running a Traveller game. None of the options are a must have, but those who are looking for more detailed rules will enjoy this supplement. Overall, a recommended buy who want more crunch for their game.
