So Long A Letter follows the story of two women from Senegal, Ramatoulaye and Aissatou. They are childhood friends whose paths diverge in adulthood when Aissatou immigrates to America, leaving Ramatoulaye behind in Senegal. The novel is told in the epistolary style—that is, it is structured as a very long letter, written by Ramatoulaye to her friend, recounting the latest events in her life and reminiscing about their shared childhood and adolescence.

The novel opens as Ramatoulaye begins her iddah, the isolation period required in Islam after the death of one’s husband. Modou, Ramatoulaye’s husband, has recently died of a heart attack, and in her letter, she describes the funeral rituals to Aissatou, who has been divorced for many years. Rama is irked that equal status has been given to her and her husband’s new, second wife, who gave him only five children to Rama’s twelve. The family gathers to divide the estate, and Modou’s wives learn that he was heavily in debt. Rama reflects on the pain she felt when Modou took another wife after 25 years of happy marriage.

In the next chapters, Rama recalls her years at the teachers’ training college with Aissatou. There she meets Modou, who is handsome and romantic. She chooses to marry him over a wealthier suitor her parents prefer, eschewing the traditional lavish wedding and customary dowry for a simple ceremony. Aissatou, meanwhile, dates a friend of Modou’s, Mawdo. Though Mawdo is of a higher class than Aissatou, being the son of a princess, the two marry in defiance of caste traditions.

Now married, the two friends experience the joys and discomforts of married life. Rama’s mother-in-law is pushy and overbearing, whereas Aissatou’s mother-in-law is openly contemptuous of her daughter-in-law, thinking Aissatou beneath her. Rama and Aissatou work as teachers, fulfilled by their careers and their youthful love. Meanwhile, Aissatou’s mother-in-law, Aunty Nabou, devises a plan to take revenge on Aissatou. She adopts a little girl whom she renames Nabou. After years of patience, young Nabou grows into a beautiful young woman. Aunty Nabou offers her adopted daughter to her son, Mawdo, and declares she will never recover if he refuses the proposal. Mawdo agrees despite Aissatou’s objections, spending every other night with young Nabou. Betrayed, Aissatou divorces Mawdo and pursues her education with a vengeance, ultimately being appointed to the Senegalese Embassy in the US and immigrating there permanently.

Three years later, Rama’s husband decides to take a second wife of his own free will. He chooses Binetou, a poor girl whose entire family will benefit from the match. He does not tell Rama of his plans until the day of the wedding, when he sends his best friend, his brother, and the local Imam to break the news. Rama’s heart breaks, but outwardly she maintains her composure and is gracious towards her husband. Rama debates whether to leave Modou, but ultimately stays, to the horror of her children. Modou ignores his first family, focusing his attention on Binetou. Rama takes on the work of running a household by herself, learning to fix leaks and pay bills. She entertains herself by talking with her 12children and going to see shows and movies, but is deeply lonely. She wonders if she will ever meet another man, but fears her many children and her lack of a true divorce would be impediments to a romantic relationship. At Aissatou’s encouragement, she learns to drive, opening up a newfound sense of independence.

Back in the present, Rama continues her ritual isolation after Modou’s death. She has forgiven him and now prays for him every day. Modou’s brother, Tamsir, arrives at Rama’s house and tells her she will now marry him. Enraged, Rama yells at Tamsir, accusing him of trying to steal his brother’s wife. Tamsir has three wives already, she reminds him, none of whom he can financially support. She refuses to marry him and Tamsir leaves, defeated. Next, Rama is visited by Daouda Dieng, the suitor from her youth, now a married man. They discuss politics and the lack of female representation in Senegal’s government. Daouda proposes marriage. After days of careful consideration, Rama concludes that she respects and admires Daouda, but she doesn’t love him. She writes a letter of explanation, telling Daouda that she also feels uncomfortable coming between him and his first wife, a pain she knows firsthand. He never speaks to her again.

Having heard that Aissatou will be coming back to Senegal to visit, Rama tells her friend about her children, some now adults themselves. Rama muses on the perils of modern parenting, how she has allowed her girls to wear pants, travel freely, and have male friends. Yet, her oldest girls have taken up smoking and partying, and she wonders if she should have been less permissive. One daughter, named Aissatou, has just revealed she is pregnant by a young law student. Though Rama is horrified by the out-of-wedlock pregnancy, she supports her daughter. The baby’s father, Iba, seeks Rama’s permission to marry young Aissatou, which she grants. Rama fumes at how Aissatou is expelled from school for getting pregnant, but boys never suffer such consequences. Determined not to let the same thing happen to her younger daughters, Rama educates them on contraception.

As she prepares for her friend Aissatou’s arrival the next day, Rama wonders what her friend will look like, after so many years in America. Will she be wearing pants? Will she insist on American furniture and utensils, like chairs and forks? Rama, for her part, will insist on keeping with tradition. She will spread out a traditional mat, and the two friends will sit and talk, just as they once did.

In So Long a Letter, author Mariama Ba grapples with changing social climates and the role women play in them, paying particular attention to the ways in which education allows women to lift themselves up, while a lack of education leaves them with few options. Through Rama and Aissatou’s shared past and divergent adult lives, Ba shapes a narrative of the many ways women can buck tradition and create new spaces and roles for themselves and their daughters.