For years they have been kept in dusty corners, hidden away in basements for fear of provoking the suspicion of repressive regimes.

But now in Egypt and Tunisia, two of the countries recently liberated from tyrannical government, there are reports of banned books about politics finding their way back onto shelves and into open conversation. At the end of this month, a book fair will be held in Cairo's Tahrir Square, which has become famous around the world as the centre and now the symbol of the Egyptians' peaceful demonstrations for freedom.

It will be a celebration of Egypt's hope for a new, democratic era, expressed through a love of the free thinking that books encourage. Earlier in Cairo's history, books were regularly burned; it was a mark of hatred and fear of the writers and thinkers whom the religious authorities wanted to drive out.

Banning and even burning books has been a feature of totalitarian regimes in Europe too, because governments that want to control a population's behaviour usually want to control thoughts and imaginations.

In Germany in 1933, soon after the Nazis came to power, they organised mass rallies at which books by Jewish or so-called 'degenerate' writers were thrown on bonfires: it made an intimidating spectacle.

Books that promote a rival religion or undermine an official religion have often been suppressed. But even works of art can be seen as a threat.

Tolstoy, possibly the world's greatest novelist, had many later works banned in his native Russia because of their Christian and political content. Parts of communist China even prohibited the sale and distribution of Alice in Wonderland, because the authorities believed its fantasy of animals with human characteristics was corrupting.

Brain food
Throughout history, governments and religious leaders have felt so threatened by ordinary readers exploring their own ideas that they have tried to control the written word.

The poet John Milton appealed against English censorship laws in 1644, writing that 'he who destroys a good book, kills reason itself.' The piece in which that quote appears, the Areopagitica, was itself banned.

Now we have minimal censorship, and can walk into a library or bookshop and feast our brains on the books. Remembering others across the globe who don't enjoy the same freedoms, and our own ancestors whose access to knowledge and imagination was limited, might make us relish even more what we find between the pages.

1. In the age of the internet and the Kindle, are the book's days numbered?

2. Censorship is an important way of limiting the influence of dangerous or offensive materials. Do you agree?

1. Design an object that tells a story or recounts a narrative but not in book form – you could take inspiration from Egyptian hieroglyphics or other pictograms. The links here should help.

2. Find out which books have been banned or censored. What are the main reasons used by the authorities?

Q Can books really change the world?
A They definitely can. Some argue that books have had more influence on human history than any other invention. Mainly this is because books contain ideas – and ideas have driven change.

Q Which books have been most influential?
A Everyone has their own list. The great religious texts: the Bible, the Torah, the Koran, the Bhagavad Gita would be on most. Certain political books such as Karl Marx's Communist Manifesto would be hard to avoid. Then great works of literature such as Shakespeare's plays have undoubtedly changed the lives of millions of people.

Q Not exactly revolutionary.
A They were. The first printed Bibles were regarded as highly subversive. In the Middle Ages people had to attend church to get their Christian teaching. With Bibles at home, church leaders feared that churches and cathedrals would be abandoned. Of course it didn't work out that way.

'Now we have Twitter, books are finished.'