Sons and Lovers (1913)
by D.H. Lawrence
Bring on the sex and psychology! And sexual psychology and psychological sexuality. If you wanted an intellectual theme for the first half of the 20th century, you could do worse than picking "Thinking About Sex: Parallel Developments in Psychology and Literature" as your choice. The narrative of Sigmund Freud occurs outside literature, but his thinking is so crucial to developments in 20th century literature that it is almost impossible to talk about 20th century literature without crediting Freud for some of the themes he brought to the table. Maybe the seminal, specific work to really pin down Freud's influence on literature is his 1899 work, Interpretations of Dreams and its concomitant ideas about the unconscious. Also crucial to his influence on literature, but less to his credit, are his theories on sexuality, many of which were outlined in the first decade of the 20th century.
You certainly can't get serious about Lawrence without first understanding how deeply he was influenced by the writing of Freud. Given the difference in language and general time lag in absorbtion of new ideas during the turn of the century period, it was plausible that Lawrence "never read Freud" as he claimed in a 1914 letter, but it is also possible that he is straight up lying, and certainly accurate that he "had heard" about Freud from multiple contemporaries who were directly involved in the psychoanalytical "movement" that trailed in the wake of Freud's most crucial contributions.
In Sons and Lovers the reader is presented with a complex Mother/Son relationship that has multiple psycho-sexual elements- along the line with what more explicitly Freudian influenced Artists would present a half century later. The main relationship is between Paul Morel and his mother, a "ubiquitous moral presence with great ambitions for her gifted son." Much of Sons and Lovers is recognizable as a successor to George Eliot and Thomas Hardy, but even in 1913 Lawrence was breaking ground in the depiction of physical sexuality in the English novel. Although 18th century literature could be quite bawdy, and while the French carried on a separate tradition of frank literature about sexual relations, the English saw it disappear for close to 160 years. Lawrence's 1920 novel Lady Chatterley's Lover was banned for almost 40 years in the United Kingdom.
Unfortunately the development of "internet pornography" has simply obliterated a couple centuries of sexual mores, making the crazed virginal attitude of Paul and his childhood girlfriend seem almost insane in comparison. Perhaps that is part of the lasting appeal- at how FRAUGHT the sexuality becomes in his books, coupled with the fact that he is the first writer in the English novel to combine sex and psychology. Man, what a winning fucking combination for 20th century art. For real.