“How little the real characteristics of the working-classes are known to those who are outside them,” lamented Marian Evans in 1856. She had reason to feel she knew better. The daughter of a Midlands estate manager, Evans grew up trudging along with her father while he collected rent from other tenants, repaired buildings, and oversaw fields, forests, and mines. As a bookish girl, she enjoyed access to the library in grand Arbury Hall—but when her father entered the big house on business, she sat with the servants in the housekeeper’s room.

Now a thirty-six-year-old literary bohemian in London, Evans…