Around 780 million adults worldwide cannot read or write.
With statistics like this, it's vital we make the most of events like World Book Day and encourage young people to make the most of reading.
The World Book Day team has provided some top tips for telling stories from bestselling authors, as well as the chance for students to pick up one of eight titles for just £1.
So what were your favourite books and authors growing up?
Here are some of the books people are talking about on Twitter:
@caitlinmoran #worldbookday Lorrie Moore's "Collected Stories", given to me by @emjaneunsworth, is another-level brilliant. It's word-parkour.
@LinkyGray For #WorldBookDayUK I'll be getting stuck into Knitting Circle Rapist Annihilation Squad by Derrick Jensen
@wesstreeting As it's #worldbookday, here are some of stonewalluk's favourite children's stories that celebrate difference: http://bit.ly/YBQWjF
@soprano_laura My favourite childhood book was 'The Farthest Away Mountain' by Lynne Reid Banks: http://en.wikipedia.org/wiki/The_Farthest-Away_Mountain …
@_XeniaKara_ My favourite book as a child was "The Lion, The Witch and the Wardrobe" we never got to dress up for it at school though#worldbookday
@rjrchilvers on #worldbookday I challenge anyone to find three funnier books than Three Men in a Boat, Under the Frog and Lucky Jim
@Scraggatron It's #worldbookday today. Perfect excuse for me to read Murakami's 'The Wind-Up Bird Chronicle' all day long. Not that I need an excuse.
@Nancy_Victor Happy #WorldBookDayUK The Book Thief by Markus Zusak is possibly the best book ive ever read!
@donne_mark For worldbookday if you haven't, I recommend Graham Greene's "A Burnt Out Case". Over-looked brilliance.
@faceforthenet On #worldbookday I would like to thank Yann Martel for writing my fave novel of all time, the beautiful Life of Pi. <3
Leave your suggestions below.