The only Zola i ever read. its about love and desire, murder and a losss of desire. They are trying it out as a play now. The book oddly enough always struck me as anthropological - about the human condition and the production of emotions, feelings and thoughts from the environment around us.
Julian Barnes does a good discussion of it:
"Those 37-year-old marginalia provoked the usual mixed feelings. On the one hand, you fear to discover that your younger self was an idiot; on the other, you need to believe that all your subsequent years as a reader and then writer have made your literary responses sharper and deeper. In terms of actual understanding of the plot, characters, key scenes and lines, I pretty much got Thérèse Raquin back in 1969, though this was doubtless helped by Zola's directness as a writer: he is explicatory rather than allusive, a teller rather than a shower. Subsequent experience brought mainly two things: a greater grasp of the psychological theories that drive the book, and a greater scepticism about - or a more nuanced response to - his picture of life...To the second edition of Thérèse Raquin, Zola added as epigraph Taine's dictum: "Vice and virtue are just as much products as are vitriol and sugar." Products, that is, of environment, inheritance, history and the momentum of the age. The human problem was one not of God and morality, but of psychological mechanics, which could be studied and solved just as a problem in physical mechanics could."