The following is based on Fallout 2 cut content and has not been confirmed by canon sources.
The Abbey was a location for Fallout 2 that was eventually cut from the game. It should be a monastery located north of Gecko, where the monks preserve knowledge in the form of books, blueprints, and items, and they tried to preserve technical knowledge mainly. Unlike the Brotherhood of Steel, who hoard their technology and used it to stay superior, the abbey is open to anyone as long as they do not damage anything. All they have to offer was knowledge, because not a single preserved item functions.
The monks do not understand the knowledge in the books they preserve. They treat them like holy materials, to be read and copied and cared for, but not acted upon.
The Abbey was to appear in Fallout 2 but was eventually cut from the final game.
Behind the scenes
The book A Canticle for Leibowitz by Walter M. Miller was the inspiration for the abbey. Much like the medieval monks of old, the monks in the abbey preserve the knowledge of a lost civilization (in the case of their forbears, Ancient Greece and Rome) in the form of books, by taking care of them as best as possible and recopying if necessary. Neither of them would truly comprehend the contents of the books, but simply copied them word for word.
↑Fallout Bible 4 Questions, questions: 2. i heard there was going to be a monastery-area in FO2, but it was not implemented in the game. It supposedly would give the player more background information on the world of Fallout. My question, thinking about how the FotA kinda worshipped 'knowledge' and 'learning a lesson out of the apocalypse', was this monastery to be the new 'base' of the FotA? "I don't know - I haven't been able to find any documentation on it, but I don't think so. From what I heard second-hand about the story and the original locations in F2, the monks at the Abbey were interested in preserving knowledge, but they were not part of the Followers of the Apocalypse... though their ideals may have been quite similar. I sent off an email to Tim Cain, and he might know, so stay tuned."
"And here's me a short while later with an answer from Tim Cain:"
"It [The Abbey] did not have the Followers there. It was supposed to be an independent organization, probably of Jesuits or something like them (I'd probably go with the latter to avoid right-wing complaints). The monks preserved knowledge in the form of books, blueprints, and items, and they tried to preserve technical knowledge mainly. Unlike the BOS, who hoarded their technology and used it to stay superior, the abbey was open to anyone as long as they did not damage anything. All they had to offer was knowledge, because not a single preserved item functioned." "One more thing: the monks did not understand the knowledge in the books they preserved. They treated them like holy materials, to be read and copied and cared for, but not acted upon. Think of the book "A Canticle for Leibowitz" by Walter M. Miller, which was the inspiration for the abbey."
"So there you have it. Coolness." "And the DJ slams in with question 3:"