There are a lot of candidates out there for the best dungeon dive, but for me, none measures up to Expedition to the Barrier Peaks. There may be better dungeons out there, sure, but I doubt any portray the boundless potential of Dungeons & Dragons like Barrier Peaks.

That’s mainly because in this case, the dungeon is actually a downed space ship, full of robots, ray guns and aliens. And boy are the monsters – or space aliens, I guess – totally weird and surprising (Froghemoth! Wolf-in-sheep’s-clothing!). Lawrence Schick (who wrote the amazing White Plume Mountain) recalls that Gary Gygax was in “full-on funhouse mode” with Barrier Peaks and it shows.

It is an old-style module, focusing on combat and traps to test players rather than characters and narrative, but boy, I can’t imagine how people reacted to playing it back in 1976. Robots? In Dungeons & Dragons? We’re allowed to do that?

That’s exactly what Expedition to Barrier Peaks is: an invitation for DMs and Players to do anything and everything they ever wanted. And that’s why it is so special.

The elaborate art booklet illustrating rooms and monsters is also a big appeal (though Tomb of Horrors also had a similar visual component). The images I’ve selected are all by the legendary Erol Otus except the wolf-in-sheep’s-clothing (there are no clear credits aside of Gygax [typical], so I’ve no way on knowing the artist).