The fact that a series of books containing anti-Semitic messages had been on the shelves of National Library Board (NLB) libraries since 2013 before being removed is worrying (Ministry asks NLB to review its book vetting process; June 9).

One may wonder how many times these books had been borrowed and read by children in the last four years.

Clearly, the NLB cannot be too reliant on a reactive and reader-led vetting process.

Are such books also available for sale in bookstores and online?

Besides pulling them from the library shelves, what is the Ministry of Communications and Information (MCI) doing to ensure such contentious literature is not circulated, especially in this digital age, where soft copies of literature can easily be found on the Internet?

The MCI and NLB need to work together to ensure that literature with objectionable content is banned from circulation here.

Perhaps the NLB could set up several multiracial and multi-religious panels to vet books before they are put on the shelves. They can also go through the NLB's large collection.

Library volunteers with good backgrounds can be tapped to be part of the panels.

Though it will be tedious work, this is a more pre-emptive measure and, hopefully, will ensure that only books with acceptable content are allowed on library shelves.

Gabriel Cheng Kian Tiong