In the 16th Century, the Catholic ChurchThe word Catholic means "universal". A Christian denomination with over a billion followers worldwide, led by the Pope. began a list of authors whose books were not to be read, known as the Index Librorum Prohibitorum. The aim was to protect the faithful from "dangerous" ideas.

By the middle of the 20th Century, the list featured some of the world's most famous philosophers, from VoltaireA French enlightenment writer, historian and philosopher known for his criticism of Christianity and slavery. to Immanuel KantA German Enlightenment philosopher who is regarded as one of the most important thinkers of the modern era. He fundamentally changed the way we think about a variety of subjects, from aesthetics to cognition to morality. to Simone de BeauvoirA French feminist philosopher best known for her book The Second Sex..

The Index was abolished in 1966. But the idea that people need to be protected from dangerous books never went away.

Some US states are now compiling their own lists of banned books. PEN America, which represents writers and campaigns for free speech, states that in 2021-22, 1,648 books by 1,261 authors were banned in schools around the USA.

Most of these bans have targeted books with a focus on race, gender and sexuality.

Advocates of the bans say they are necessary to protect children. They insist they only affect children under fourteen, who are too young to be accessing content about sexuality and gender.

And, they say, this is also too early to teach them about race. They claim that children are being taught to obsess over racial differences, and that this only deepens divisions.

But critics say the bans are not about making reading age-appropriate. They aim to stop young people from reading about the lives of LGBT+ people and people of colour.

Fully 41% of all the books that have been banned have LGBT+ themes or characters, while 40% have prominent characters of colour. Only 22% include sexual content - around the same proportion as those with titles that feature issues of race and racism.¹

Among them, for example, is Judy Blume's Are You There God? It's Me, Margaret, a film adaptation of which will be released this year. The book is frank about puberty, same-sex attraction and religious faith.

Books, they say, play an important role in expanding children's horizons. If they read books with LGBT+ characters and characters of colour, they are more likely to be accepting and tolerant.

But others are more optimistic. They say banning books can give them a new lease of life. Telling children that some books are bad for them could backfire if it makes reading them seem more exciting.

Yes: Once we have set the principle that young children should be shielded from "dangerous" ideas about race, sexuality and gender, we are not far from banning those ideas everywhere.

No: These are not general book bans: they are just aimed at ensuring that younger children only read things that are appropriate for their age. Older children and adults will still be able to read what they like.

Or... These bans may not have the impact their creators intended. Saying that an idea is dangerous and needs to be banned will always draw more attention to it.