I have not verified this story, take it for what it's worth.
This is a story from The New Criterion magazine's blog. A patron suggested a title for the Brooklyn Public Library to add to their collection. The book is called Londonistan and it deals with radical Islam in England. Supposedly, a collection development person at BPL emailed back this response:
Thank you for your question. Normally, the library doesn't add a nonfiction title to the collection (and especially one that is potentially incendiary) unless a review from a trusted source (professional journals) can be found. Unfortunately, we have not found such a review for Londonistan. Therefore, at this time, the library will not be adding Londonistan to the collection.
Perhaps I understand the professional journal review requirement; however, it sounds more like a convenient excuse when the book is characterized as "potentially incendiary."
As I wrote, I haven't verified this story so I don't know if this is all there is to this story. Sure is interesting.
Here is a link to The New Criterian blog: