Edith Wharton kept restlessly editing her best sellers even through numerous print runs. In 1921, she finished fine tuning “The Age of Innocence” upon its sixth printing and tucked one edition onto the shelves at her chateau in Southeastern France.

That copy, with her signature and bookplate, has resurfaced in time for the centennial of the Pulitzer Prize-winning novel. It has been donated to the library at another of her palatial homes, the Mount, a museum in Lenox, Mass.

This is the only known English-language version of “The Age of Innocence” that belonged to Wharton, said Susan Wissler, executive director of the museum. (Examples of the writer’s copies of many of her works are already at the Mount; gaps include her collected teenage poems.) Ms. Wissler added that the museum’s book collection, as it grows, powerfully evokes Wharton’s interests and presence: “The library very much provides us with her soul.”

The “Age of Innocence” copy, a gift from the book collector Dennis Kahn, will be unveiled on Jan. 24, Wharton’s 158th birthday. Mr. Kahn bought it from the book dealer Sarah Baldwin in 2002 for $2,500 (it was recently appraised at $12,500). Wharton aficionados “don’t know how it escaped” from the writer’s library, Mr. Kahn said.