Lolly Willowes, or The Loving Huntsman by Sylvia Townsend Warner

After spending two decades of her life as a put-upon spinster aunt, Laura Willowes decides to make a change, sparked by a bundle of greenery she picks up in a shop. To the befuddlement of her staid family, she ups sticks and moves to a remote English village called Great Mop, where she makes a deal with the devil to finally have the life she wants, which involves witchcraft, a cat familiar named Vinegar, and a great deal of exhilarating, bittersweet freedom.

A very, very fun read, esp. on gleamy October days when golden leaves waft down like a fistful of coins scattered in a fountain.