When it comes to banning a book, who exactly draws the line?

A look at libraries across Canada, the US and the UK reveals there are strict procedures behind every call to take a book down from the shelves.

Most often, members of the public, such as concerned parents, will complain to their library after coming across books they deem inappropriate for their children.

Library staff will investigate before deciding if it warrants withholding access to the offending book.

In the Brooklyn Public Library (BPL) in New York, for example, a patron complained that the comic book Tintin Au Congo depicted Africans in a racially offensive manner.

The objection was reviewed by a panel, which decided to store copies of the comic in a room accessible only to staff members.

But this seldom happens as the BPL abides by a policy of not unjustly pulling materials even if they may offend a patron.

Parents seem to have a significant influence in the banning of children's books in the UK.

Hundreds of complaints from parents were reviewed by librarians and books determined as containing inappropriate themes were taken off the shelves.

In Vancouver, a book on serial killing was sent to the hate-speech squad at the Vancouver Police Department.

Although the reader criticised the book for having no educational benefit to children, the Vancouver Public Library stood by its obligation to protect the right of any citizen wanting to read the book.