This 1994 book by Julia Alvarez is based on the true story of four sisters, Patria, Dede, Minerva and Maria Teresa "Mate" Mirabal, during the dictatorship of Rafael Trujillo in the Dominican Republic. The sisters make a political commitment to overthrow the Trujillo regime. They are harassed, persecuted, and imprisoned, their family suffers retaliation from the Military Intelligence Service (SIM), and they are eventually killed. The book presents the perspective of each, including the one surviving sister, Dede. The book was made into a movie starring SalmaHayek in 2001.
* CodeName: The Mirabal sisters are known in the resistance movement as "Las Mariposas" (the butterflies), hence the book title.
* DeliberateValuesDissonance: For example, Patria and Pedrito are teens when they get married, everyone is aghast that Minerva wants to wear pants and go to college, plus the multiple examples of KissingCousins.
* DirtyOldMan: Trujillo is portrayed this way. Minerva's first encounter with him is when he falls in love with her teenage classmate Lina Lovaton, gets her pregnant, and moves her into her own house. Later on he tries to come on to Minerva herself.
* ForegoneConclusion: It's stated in the book summary that the sisters are killed.
* FourthDateMarriage: Patria and Pedrito get married when she is 16 after a few months of dating.
* FrameStory: The chapters told from the point of view of Dede are presented as Dede recounting stories to an interviewer, and Maria Teresa's chapters are told as diary entries.
* HormoneAddledTeenager: Maria Teresa.
* KissingCousins: Dede and Jaimito are married, and Maria Teresa has a brief LoveTriangle between her two cousins Berto and Raul.
* MakeItLookLikeAnAccident: Minerva, Maria Teresa, and Patria were beaten to death and then placed back in their car to make it look like it was a car accident. However, everybody knew that the government had done it.
* TheMistress: Papa has another family with a poor woman.
* PlayAlongPrisoner: When Minerva and Mate are imprisoned for their political activities, they are offered a pardon but Minerva refuses because that would imply that they committed a crime.
* PoirotSpeak: Happens a lot with Spanish.
* PrisonRape: Happens when Minerva and Maria Teresa are in prison.
* SexIsEvilAndIAmHorny: Happens with Patria when she is at convent school. Despite wanting to become a nun, she describes her hands "wandering" and having the desire to lick the fingers of all the young men who come into her father's shop.
* SoapboxSadie: Minerva.
* SoleSurvivor: Dede. Much of her chapters focus on why she survived and the other sisters didn't.
* SwitchingPOV: Switches between the 4 sisters. Most obviously, Dede's chapters are told in limited 3rd person POV while the rest of the sisters' stories are told in first person.
* TooGoodForThisSinfulEarth: Mama thought that Patria didn't have a long time left on the earth when she was little because she was so loving. Also invoked, because the Mirabal sisters are seen as martyrs (both in the book and in real life).
* VeryLooselyBasedOnATrueStory: An example of TropesAreNotBad here. Julia Alvarez outright admits that she imagined their thoughts and motivations.
* WhereAreTheyNowEpilogue: Well, it's more of a "Where Are They in 1994 Epilogue". In a way the last chapter is this. Dede remembers what happened to the families of her 3 sisters and where they are now.