Philip K. Dick.
I guess this could be classified as a humorous tragedy. Joe Fernright is a “pot-healer”–he fixes ceramic pots in a distant future communist society, which means he’s fairly useless. An immensely powerful & almost godlike alien creature contacts him (as well as others from various planets) to help him (the alien) raise a cathedral which has sunk in the sea.
Once on the planet, Joe and his new girlfriend Mali dive underwater to discover that there are two cathedrals–the cathedral, and the anti-cathedral. Also, this alien the Glimmung, has an anti-Glimmung–a dark one, who is part and parcel of being a Glimmung–and who wants to destroy it. Joe also sees his future corpse down there under the sea. His corpse advises him to raise the cathedral.
Glimmung and dark one fight, Glimmung is badly injured & envelops all his employees who now must truly commune to help him. All along, Dick makes references to Glimmung as Faust, so we are surprised to see that he/they do actually raise the cathedral. Joe and one other opt to leave Glimmung but the rest–including Mila–choose to stay as part of him. Joe attempts to create a pot rather than heal one; and succeeds only in making a really bad one.
Fairly decent novel, but certainly not his best. The strange plot & world make about as much sense as do most dreams–there’s some sort of over-arching sense to the whole thing, even if it is composed of parts which are utter nonsense.