While you surely know of the ominous world that The Handmaid's Tale takes place in from the promos for Hulu's new series, you may not know exactly what the titular handmaid does and why. Based off of Margaret Atwood's 1985 dystopian novel, women become handmaids in The Handmaid's Tale because it's the law and not of their own volition. In the future that Atwood created, women are less than second-class citizens and the government classifies them by what they can provide to men. Handmaids are just one of the categories of women in The Handmaid's Tale — and the purpose they serve is particularly disturbing.
In the novel, a fundamentalist Christian group named the Sons of Jacob takes over the U.S. and turns it into the Republic of Gilead. This group is fixated on literal readings of the Bible and creates social classes based on the Old Testament. With this radical view comes no respect for women other than what they can provide to men and so women in Gilead have lost all rights and are forbidden to read. Further complicating matters is a plague of infertility that is sweeping Gilead. While both men and women are infertile, only women are blamed for it by the government. So in order to have the male leaders of Gilead continue to reproduce, they created the handmaids.
The classes for women in Gilead are broken up into "legitimate" and "illegitimate" women. The legitimate women in The Handmaid's Tale include wives, aunts, daughters, Marthas, econowives, and handmaids. The illegitimate women are jezebels and unwomen. Each of these groups have been created by what purpose they serve to the men and the handmaids are made up of the remaining cooperative fertile women. They are tasked with producing children for the leaders of Gilead ("commanders") and their wives. If a handmaid is unable to bear a child for a commander in six years (that's three two-year assignments with three different commanders), she is classified as an unwomen. Unwomen do not follow the Republic's rules and are sent to labor camps in the polluted colonies.
Women who are handmaids are assigned to a commander and have sex with him while his wife is in the room for the sole purpose of procreation — or so the men say. If the handmaid has a child, it belongs to the commander and his wife — not the woman who gave birth to the baby. In Hulu's version of the book, Elisabeth Moss played Offred — the main handmaid of the story, who serves Joseph Fiennes' Commander Waterford and his wife Yvonne Strahovski's Serena Joy.
Atwood described how the inspiration for the handmaids in Gilead came from the Old Testament in a 2017 article for The New York Times:
The Sons of Jacob clearly took their reading of the Bible to a frighteningly literal level and created their entire society and the handmaids from it. While no women are treated well in the Republic of Gilead, the handmaids — and the systematic rapes that they are victims to — perfectly represent how bad a patriarchal society can become.