Family Drama/Coming-Of-Age
If you're the kind of dude or dudette who likes math, we'd suggest that you could split this book nearly 50/50 between the categories of Family Drama and Coming-Of-Age. On the one hand, the book's first part mostly deals with the dynamics of the Morel family. You can see this family dynamic emerge in the resentment that Mrs. Morel harbors toward her alcoholic husband Walter:
At the wakes time Morel was working badly, and Mrs. Morel was trying to save against her confinement. So it galled her bitterly to think he should be out taking his pleasure and spending money, whilst she remained at home, harassed. (1.194)
This first section of the book ends in William's death and Paul's first meeting with Miriam. From that point on, the book focuses more on Paul's coming-of-age as a painter:
When he was twenty-three years old, Paul sent in a landscape to the winter exhibition at Nottingham Castle. Miss Jordan had taken a good deal of interest in him, and invited him to her house, where he met other artists. He was beginning to grow ambitious. (10.1)
The second part of the novel also focuses on Paul's attempt to negotiate between his love for his mother and his love for Miriam Leivers and Clara Dawes. This negotiation does not end well, as Paul ultimately loses all three women. Tough luck, Mister.