Today I'm recommending Zeikin de Katta Hon by author Zuino and artist Keiyama Kei.
What would happen if a delinquent got a job as a librarian? Nothing you'd imagine to be honest. This guy has a fondness for books and actually cares, and it's a funny way to look into what runs a library in Japan. Fun characters and fun subplots make this manga very much worth reading.
All around, I highly recommend this series and you should definitely check it out.