Virgina Woolf declared Middlemarch “one of the few English novels written for grown-up people”. Henry James said that some of its scenes were the most intelligent in English fiction. Even Martin Amis, over 100 years later, called it “a novel without weaknesses”. Now this 900-page portrait of 19th-century provincial life has been voted the best novel of all time in a Guardian poll of writers, academics and critics.

George Eliot (the pen name of Mary Ann Evans) was already a highly successful novelist by the time Middlemarch was published in instalments in 1871 and 1872. Beginning with a marriage, and a deeply unhappy one, it upends “the marriage plot” established by Jane Austen. Nineteen-year-old Dorothea Brooke has “a passionate desire to know and to think”, and a longing “to lead a grand life here – now – in England”. Unfortunately, that England didn’t afford many opportunities for women, and she misguidedly hitches her idealism to the desiccated scholar Casaubon. This is not the novel’s only disastrous marriage. The ambitious young doctor Tertius Lydgate makes an ill-suited match to the vain and shallow Rosamond Vincy.

The novel is set 40 years before it was written, just before the Reform Act of 1832 and the arrival of railways. England is on the brink of change: the enfranchisement of the middle classes and the end of an old order. But reform in the novel is about more than politics. Eliot’s characters want to change the world. Instead, the world changes them, as their ideals are confronted by reality.

In placing an intelligent, high-minded young woman at the centre of her novel, Eliot reshaped English-language fiction. Elizabeth Bennet and Jane Eyre may have paved the way, but without Dorothea we wouldn’t have James’s Isabel Archer or Woolf’s older Mrs Dalloway and Mrs Ramsay. There is a clear path from Middlemarch to the female interiority of Sally Rooney’s novels today.

Eliot herself is a wise and gracious voice in the novel, breaking the fourth wall to remind us to look or think more carefully. For her, shifting point of view was not so much a literary technique as a moral obligation. Empathy is an overused word today, but for Eliot it was almost a religion. She had lost her faith, but showed that divinity can be found through true fellow feeling.

This moral seriousness is sometimes mistaken for moralising, and Eliot as dull and preachy. Although admired, she is not held with the same affection as Austen or Dickens; her novels don’t lend themselves so readily to TV or film. They are not embedded in the public imagination like those of the Brontës. Neither Kate Bush nor Charli xcx felt moved to write pop songs about Middlemarch.

The magic of the 19th-century realist novel is succumbing to its world for hundreds of pages, and never more so than when reading Eliot’s masterpiece. It is a joy to live among the gossipy, imperfect inhabitants of Middlemarch. The backdrop of local elections and national uncertainty are particularly timely, as are its lessons on sympathy and tolerance. As Amis observed, “it renews itself for every generation”.

This is a novel about what it means to be good. And it is impossible to emerge from it unchanged. It is a celebration of the quiet heroism of unremarkable lives, all those who “rest in unvisited tombs” as the melancholy last line has it. With Middlemarch, Eliot showed what a novel could do.