There are numerous "man vs. society" conflicts in Alvarez's novel.  Of course, there is a free society vs. a dictatorship, ie, Trujillo's reign vs. the "movement" for freedom that Lio and Minerva fight for.  In Trujillo's dictatorship, no one can freely express their opinions or opposition to the government without severe consequences:  prison, or even death. 

One particular example that comes to mind is when Minerva watches her dear friend at boarding school become one of Trujillo's concubines.  This is one of the first times that the brutality of Trujillo's regime hits home for Minerva.  She realizes that women are less than pawns in her society which treats females as property, with nothing to offer but their sexuality.

A theme, therefore, of the novel, is valuing women for their contributions to society, beyond being a good wife and mother.  Politically, can often equal (and frequently surpass) the efforts of men.  While men like Minerva's father kowtow to the government, Minerva challenges the status quo in order to make life better for her fellow man and woman.  Although she will not live to see her country change for the better, her valiant efforts in the face of oppression will yield results that would never have been realized without the opposition of women like her.