Reading and writing are forbidden for the women of Gilead, as these activities might give them ideas, and in this misogynistic dystopia, that's the last thing that the men in charge want.

Throughout history, illiteracy has often been used as a weapon of control by the ruling classes, and the same dynamic can be observed at work in Gilead. If women are able to read and write, then they'll be able to communicate with each other. This would threaten the powers that be, as it might encourage women to join together and resist this barbaric regime.

From the point of view of Gilead's ruling class, female literacy would also have the baleful effect of allowing women to develop horizons beyond the narrow dystopia in which they live. The men in charge are determined to control reality, and that means ensuring that women only believe what the men want them to believe. And what better way to control reality than to prevent women from reading and writing?

For the rulers of Gilead, enforced illiteracy has the added advantage that it prevents women from reading the Bible and finding something in it which they can use to challenge their subservient position. The men know full well that the powerful, revolutionary message of Jesus could so easily be used against them, that the women of Gilead could draw upon the Word of God and challenge the fundamentalist interpretation of Scripture that shapes and controls life in Gilead.

The ability to read and write is reserved for men in the dystopian, totalitarian world of Gilead. This is one of many strategies designed to keep women subjugated, and it’s taken pretty seriously, with the penalty being having a woman's hand cut off if she is caught reading. Consider the old adage of knowledge being power. It stands to reason that since the powers-that-be want to keep women ignorant and suppressed, reading should not be allowed.

Being able to read and write would also give the women enslaved in Gilead more chances to strategize and make plans for escape. By making sure that women can only verbalize their thoughts (and often have to resort to lipreading for any kind of privacy), the authorities successfully make it very difficult for women to share a secret or covert thought.

In addition, let us consider the role of the Bible in this society. Gilead is meant to be based on scripture, and if women had permission to read, they would soon realize that the powers-that-be are adopting some significant creative license in their reading and interpretation of the Bible.

Lastly, by banning women from reading and writing, the authorities ensure that the next generation of women to grow up will not even know how to read or write, which will make them so much easier to subjugate.

Reading and writing are forbidden for a number of reasons:

First, women are forbidden to read and write because the government of Gilead does not want them to be able to communicate with one another secretly. They cannot send one another letters or messages that they might use to start or join a resistance. Since they are deprived of all modes of communication besides verbal speech, the women's communication can be much more tightly controlled, because it can be monitored: overheard, caught on video, and so on.

Second, reading is one major way that people educate themselves. When we read, we learn about other people and other societies, and we expand the way we think about the world. The Gileadean government does not want women to be educated or thoughtful. They are supposed to be obedient and submissive. In fact, if you think about it, it is only the first generation of women in Gilead who will be literate. After them, if no women learn to read or write, they will be so much more docile and compliant because they simply will not know another way. They will not be able to read stories about heroes who stand up to injustice, and therefore, they might not even have a way to identify injustice when they see it.

Third, by keeping the Bible—which Gilead claims to take as its foundational text—secret, the government can control consumption of it. The government can prevent people from reading inspirational stories that might compel them to action and only allow citizens to come in contact with the stories that would seem to support their society. Further, they can make changes to the Bible, some subtle and others not so much, in order to suit their own end—Offred is aware of some of these changes and points them out to us.

In Margaret Atwood's The Handmaid's Tale, reading and writing as a whole are forbidden entirely for all women. The novel takes place in a dystopian society in which women, under extreme oppression, are taught to believe that their only value of existence is to mother children. For these women free speech, free thought, romantic relationships, and any significant emotion are all banned. As a consequence, reading and writing, which often strongly embody all of these traits, are also banned. Towards the beginning of the novel, Offred speaks:

It's also a story I'm telling, in my head, as I go along.Tell, rather than write, because I have nothing to write with and writing is in any case forbidden. But if it's a story, even in my head, I must be telling it to someone.

In this society (which is called the Republic of Gilead), women are forced to talk secretly in whispers, to read each other's lips, and to avoid obvious communication at the risk of being punished. Offred, along with some other of the Handmaids, attempts to resist conforming to this absurd society.