I really liked this book and its variety of information and spent the night reading it.
Some of the information may be outdated, but I think that others are still useful to know (how to deal with people challenging your library, deal with harassment in your library, basics like the Dewey & Library of Congress cataloging systems, how to provide good service to LGBT folks, seniors, disabled people, etc.) and could be an ok introduction. The trivia and historical/folkloric facts were great, there was a lot of that.
There's a whole list of movies having something to do with libraries. There's also a part about how to protect and recover a collection of books and records from water damage.
So, a lot of it was useful/interesting to me even though I am not a librarian.
TW for ableist language and mentions of harassment (also if your psychotic episodes involved ghosts you might want to avoid the list of haunted libraries)