You could say that The House of the Spirits is a story of class struggle. Yes, it's a family saga, a love story, and a history lesson, too. But all of these aspects are affected by the class structure that divides society into two basic groups – the white, educated elite of European descent who control politics and business, and the poor workers and peasants of indigenous ancestry who have little access to education or political enfranchisement. The resentment that builds as the characters struggle against this oppressive class structure propels much of the action of the climactic final chapters.
Class operates in The House of the Spirits as an oppressive matrix that promotes inequality and injustice – its inflexibility makes it impossible for any of the characters to rise above their class, no matter how hard they work or how much they accomplish.
In the House of the spirits, upper-class individuals who try to improve the lives of peasants and workers fail to achieve any real social change. The fact that they can't relate to the reality of the impoverished class, who must struggle to survive and to meet their basic needs, makes them an ineffectual force for social change, and confirms Ana Díaz's idea that the bourgeoisie shouldn't be allowed to meddle in the affairs of "the people."