This is an intense and melodramatic novel, one of a series (I was astonished to learn) of 20 novels called Les Rougon-Macquart. It is about the miners and their employers in the Northern France of the Second Empire. It is set in the 1860s.
The novel is really a social commentary, with plenty of time devoted to descriptions of the miners and their communities and the bourgeois lifestyles of their employers.
At the heart of the novel lies the brutality and repression of employment in the mines. Metaphors of great beasts swallowing up men and killing them off or wasting them away to destruction abound. It is a very well wrought description of the inhumanity of mass labour. There is also a strong theme around sex and sexual licence. The miners are described as being at it like knives, openly and with abandon. This is contrasted with the repression of desire on the part of one of the bourgeois owners and the licentiousness, albeit in more luxurious surroundings, of his wife. So morality is a variable concept in the novel, though the immorality and evil of mass exploitation is everywhere evident.
The main character, or one of them, Etienne, becomes a political organiser and a socialist autodidact. As he acquires learning, he feels increasingly distant from the miners, becoming impatient with their inability to embrace intellectual ideas. We see a nascent bourgeois. Or do we? Is the idea of a learned member of the working class a contradiction in terms? Personally, I hope not. I think high culture can be enjoyed by all, regardless of economic position. But this is hard to put into practice, in any society. Perhaps I am being idealistic and the tendency to embrace and participate in high culture only comes with the leisure and confidence of relative wealth. It would be nice to think otherwise, however, so I do.
The novel includes some implausible events and it is, as I say, melodramatic. But it is very involving and it made me question again and again why we allow working people to suffer and lead lives of oppression, all in the name of economic efficiency.