Monday Starts on Saturday - Arkady Strugatsky, Boris Strugatsky (Monsef)

Sasha, a young computer programmer from Leningrad, is driving north to meet some friends for a nature vacation. He picks up a couple of hitchhikers, who persuade him to take a job at the National Institute for the Technology of Witchcraft and Thaumaturgy.
The adventures Sasha has in the largely dysfunctional institute involve all sorts of magical beings—a wish-granting fish, a tree mermaid, a cat who can remember only the beginnings of stories, a dream-interpreting sofa, a motorcycle that can zoom into the imagined future, a lazy dog-sized mosquito—along with a variety of wizards (including Merlin), vampires, and officers.
First published in Russia in 1965, Monday Starts on Saturday has become the most popular Strugatsky novel in their homeland. Like the works of Gogol and Kafka, it tackles the nature of institutions—here focusing on one devoted to discovering and perfecting human happiness. By turns wildly imaginative, hilarious, and disturbing, Monday Starts on Saturday is a comic masterpiece by two of the world's greatest science fiction writers.