Lady Chatterley's Lover by D. H. Lawrence remains his most controversial book. It was banned almost immediately in several countries for pornographic material. The plot follows Lady Constance Chatterley, referred to by her nickname of Connie, and how she regains a sense of her own person through finding sexual gratification and love with her estate's gamekeeper, Oliver Mellors.
However, these sex scenes reflect the themes and message of the book as a whole, and I do not believe the book would be the same without them. To begin, the core themes of Lady Chatterley's Lover include love, sex, individuality, and freedom. The former two and the latter two are both tied together - according to Lawrence, sex and love go hand in hand, and the individuality and freedom expressed across the book are also intrisically tied. By finding sexual love, we can find our own individuality and freedom.
For example, in the beginning of the book, Connie has not had real passionate sex for a very long while - since she married Sir Clifford. Paralyzed from waist-down, Connie and Clifford are unable to have children or sex in general, which remains a wish for the inheritance of Clifford's baronetcy. Their love is not one of passion but one of habit. As a consequence, Connie feels older than she is and tired of life.
The first sex scene of the book occurs when Connie and Clifford's home is visited by one of Clifford's artistic friends, Michaelis. Connie and Michaelis have sex several times, but during the only time that is outlined clearly, Michaelis comes to his climax before Connie, yet she forces him to continue having sex until she also does. They're fundamentally disconnected from the idea of sex as a action of passion and love, and additionally that shows how they are ill matched for one another.
Although for the first two times that Connie and her main love interest Mellors have sex Connie is almost nonresponsive, the third time both of them reach their sexual climax at the same time. Unlike Clifford and Connie, who never have sex, or Michaelis and Connie, who are mismatched, or Mellors and his own wife, who are estranged, Connie and Mellors' simultaneous orgasms symbolize passionate love.
Although Connie and Mellors never speak one another's names, it's undeniable that Connie grows more into herself throughout the progression of their affair. Whereas in the first few chapters Connie is a passive presence in her husband's discussions with his friends, she evolves to challenge him more and more, and whereas before she floats through life, she evolves to stand on her own and make her own decisions, the passionate love she finds with Mellors assisting her in finding her own freedom.
The book makes the fundamental argument that passionate sex is the realization of the individual. And although Lady Chatterley's Lover ends ambiguously, with a waiting stage as Mellors and Connie wait for divorce from their respective spouses, it's clear that the sex they had together brought them to stand for what they wanted. Mellors, after years of estrangement from his wife, actually begins the process of divorce, and Connie, instead of being passive with her husband, decides to try to leave him for a life that she wants. And sex, D. H. Lawrence argues, is the process as to realize the individual.
Of course, I don't really believe in D. H. Lawrence's points myself (being generally uninterested in the act), but it is up to the individual on whether you agree or disagree. Nonetheless, I think Lady Chatterley's Lover is a good read nonetheless.
After finishing the book, I immediately began reading D. H. Lawrence's own a propos of the story. I'll leave you with his opinion: the act of sex is not nearly as important as the ability to truly understand it.