Expedition to the Barrier Peaks is a 1980 adventure module for the Advanced Dungeons & Dragons role-playing game written by Gary Gygax.

Expedition to the Barrier Peaks was first played at the Origins II convention in 1976, where it was used to introduce Dungeons & Dragons players to the science fiction game Metamorphosis Alpha.

Expedition to the Barrier Peaks comes with a booklet of 63 numbered illustrations, depicting the various monsters, high tech devices, and situations encountered in the adventure.

Along the way, the characters find colored access cards and futuristic devices such as blaster rifles and suits of powered armor that they can use to aid their journey.

In the sixth and final section, the activity deck, the players' characters must contend with various sports robots, including a "boxing and wrestling trainer" and a "karate master".

Gary Gygax thought it would be a good idea to introduce science fiction/science fantasy concepts to D&D players through the use of a tournament scenario at the 1976 Origins II gaming convention in Baltimore, Maryland.

Gygax started with his old Greyhawk Castle campaign material and added a spaceship, which Rob Kuntz helped him populate with monsters.

[5]: 2 When Metamorphosis Alpha was updated and expanded into Gamma World, it seemed the right time for Gygax to reintroduce Expedition to the Barrier Peaks to the public.

"[5]: 2  Gygax updated the scenario to Advanced Dungeons & Dragons (AD&D) rules, hoping it could serve as a primer on how to integrate science into one's fantasy role playing game.

At the time of Expedition to the Barrier Peaks's release, each Dungeons & Dragons module was marked with an alphanumeric code indicating the series to which it belonged.

S3 Expedition to the Barrier Peaks was Gary in full-on funhouse mode, having a high old time mixing elements of Jim Ward's Gamma World with fantasy to create a rollicking and memorable AD&D adventure.

[17] In December 2019, Goodman Games published Original Adventures Reincarnated #3: Expedition to the Barrier Peaks under license from Wizards of the Coast.

30), Tim Byrd gave a favorable review, stating that it "successfully combines fantasy with SF" and that it was "extremely fun to play [...] one of the best modules TSR has published".

[22] In the August 1981 edition of White Dwarf (Issue #26), Marcus L. Rowland said in that he found the adventure "very enjoyable, with ideas and creatures eminently suitable for wider use".

He gave it 9/10 overall, but complained that some of the maps were printed on both sides of the same sheet, making them useless as a Dungeon Master's shield[23] (a visual barrier that allows dice rolls and other activities to be conducted without the players knowing the outcome.

[23] In 2004, on the 30th anniversary of the publication of D&D, Dungeon magazine published a list of The 30 Greatest D&D Adventures of All Time and ranked Expedition to the Barrier Peaks as 5th.

[29] Aaron Starr for Black Gate said "The best 'official' genre bending I ever saw was an adventure module for AD&D [...] called Expedition to the Barrier Peaks.

"[30] In his 2023 book Monsters, Aliens, and Holes in the Ground, RPG historian Stu Horvath commented on the effect this adventure had on fantasy role-playing, saying, "Taken in sum, the invasion of science fiction in Expedition to the Barrier Peaks seems like an invitation.

If Gygax, who was so often interested in D&D's uniformity, can flip the script with robots and lasers, and generally embrace this silly romp for what it is, imagine what typical players can do with Dungeons & Dragons.