It is described as a basic right and a foundation for life-long learning, but the United Nations says millions of people around the world are still unable to read and write.
Security is challenging all the development processes in Afghanistan, that includes the development process of education .... Still we have hundreds of schools which are closed because of security concerns. And we still have two million children which are out of the schools. They can't go to school because of these problems .... 50 percent of the schools have no buildings ....
A statement released by the UN's education arm, UNESCO, to mark International Literacy Day said: "Literacy is much more than an educational priority - it is the ultimate investment in the future. We wish to see a century where every child is able to read and to use this skill to gain autonomy."
According to UNESCO, almost 774 million people in the world lack basic reading and writing skills, and of those, almost two-thirds are women and girls.
Some 123 million young people, aged 15 to 24, are unable to read and write, and again the female share is more than 60 percent.
The lowest literacy rates are in south and west Asia, which is home to half of the global illiterate population, and sub-Saharan Africa, which has some of the lowest rates - below 50 percent in 10 countries, and dropping to 25 percent in Guinea.
Providing universal primary education is among the UN's eight Millennium Development Goals, and there has been progress.
By the target year of 2015, two-thirds of adults and three-quarters of youth in sub-Saharan Africa are expected to be able to read and write, and in south and west Asia about nine out of 10 young adults are projected to be literate.
But obstacles remain as the world strives to provide education for all.
So what are the challenges facing UNESCO? Why are so many people still unable to read and write? And what can be done to educate girls and women across the world?
Inside Story, with presenter Shiulie Ghosh, is joined by guests: Jordan Naidoo, a senior adviser on education for the UN children's charity UNICEF, and Kabir Haqmal, the director of Information and spokesman for Afghanistan's minister of education.
"There has been immense progress over the last 10 to 15 years ... but it still needs a lot more attention to providing access [to education] for girls that [is] closer to the communities, where girls don't have to travel too far, because parents and community members see the issue of threats along the way. But [we also need] ... to encourage parents and community members to see the value of education for all children, not just boys.
While literacy rates in general have increased, women still make up over 60 percent of those that are illiterate. There's a number of reasons and one of the main reasons is that even when girls are enrolled often they are forced to drop out for various reasons .... I think one of the main reasons remains social attitudes, but it's also a question of providing infrastructure, schools closer to communities ... we also have to change teaching practices .... The issue is not only about access but also improving the quality of learning .... Often, even when girls are enrolled, they face many other problems - acute discrimination, [a] curriculum [that] is not accurately matched to the needs of all children .... We have to work on access, quality and other measures to ensure that girls not only get into school but actually do learn."
Jordan Naidoo, a senior adviser on education for the UN children's charity UNICEF