Start with The House of Mirth. It is the novel where Wharton found her subject and her method at the same time: Lily Bart, beautiful and nearly rich, must marry well within a narrow window, and the book follows the mechanics of her decline with a precision that never once softens. It is her most gripping novel, it is the one that best rewards a first reading, and its final fifty pages are as merciless as anything in American fiction.
The obvious alternatives are both worse first choices. The Age of Innocence won the Pulitzer and is the more perfect book, but its restraint reads as coolness until you know what she is doing. Ethan Frome is the one assigned in schools, and it is a bad introduction to Wharton — a short, grim New England tragedy about poverty and a sledding accident, formally unlike everything else she wrote, and often the reason readers assume she is a dour writer. She is not; she is a savagely funny one.
The two New York novels
The House of Mirth, then The Age of Innocence. They bracket her career — 1905 and 1920 — and they examine the same closed society from opposite angles: one from the position of a woman who cannot afford to fail, one from a man who has every advantage and uses none of them. The Age of Innocence is quieter and it is the greater book. Its subject is what a rigid social code costs the people who obey it, and the cost is calculated in a single, devastating final chapter set decades later.
The Custom of the Country, which is the sharpest of all
The Custom of the Country is the one to read third and the one long-time readers most often name as their favourite. Undine Spragg is an ambitious, incurious, entirely unsentimental young woman from the Midwest who marries her way through New York and Paris, and Wharton refuses to punish her or redeem her. It is the funniest and the coldest of the novels, and it has aged into a startlingly modern book about ambition without any accompanying interior life.
If you liked The House of Mirth and want more of the same acid, this is it.
Ethan Frome, in its proper place
Now read Ethan Frome, once you know what Wharton usually does, so that its differences register as choices rather than as her default mode. It is barely a hundred pages, it is bleak, and it is deliberately stripped of the social comedy that powers the New York novels. Read this way it is an impressive exercise. Read first, it misrepresents her entirely.
The ghost stories
The Ghost stories of Edith Wharton is the underrated corner of the work, and it is a genuine surprise for readers who know her only as a novelist of manners. The stories are quiet, controlled and unnerving, and several of them — the ones about servants, houses and things half-seen — are as good as the form gets. They also make a useful argument: her real subject was always what a household conceals, and the supernatural stories just remove the manners from the equation.
What is missing, and where to stop
This path omits several books worth knowing about: The Reef, the most Jamesian of her novels; Summer, a frank rural novel that shocked its first readers; The Buccaneers, unfinished at her death; and A Backward Glance, her memoir. Their absence is a catalogue gap rather than a verdict.
Where to stop is easy here. Read The House of Mirth, The Age of Innocence and The Custom of the Country and you have read the Wharton that matters; the other two on this path are for readers who want more. There is no late decline to navigate and no difficult final phase — the difficulty with Wharton is only that the school system picked the wrong book.
Follow the full ordered path here: Edith Wharton Reading Order: Where to Start.