THE GIRL WITH GLASS FEET

By Ali Shaw

287 pp. Henry Holt & Company. $24

In myths and fairy tales, characters frequently shapeshift. Arachne becomes a spider. Midas' daughter turns to gold. A frog winds up a prince. These stories speak to a persistent human concern: Our lives as we know them are temporary, subjected to merciless change. Merciless change is on full display in ''The Girl With Glass Feet,'' Ali Shaw's fantastically imagined first novel. The story is as straightforward as the title suggests: Ida Maclaird, the book's protagonist, has feet that are turning to glass.

More than a striking image, Ida's transformation serves as the novel's central crisis. Searching for clues to her condition, Ida returns to a set of northern islands she once visited. She hopes to locate a recluse who told her he'd seen ''glass bodies . . . hidden in the bog water.''

The winter coastline of St. Hauda's Land features only ''the insidious sea.'' Inland lie ''foul-smelling bogs and haggard woodland.'' Concrete-colored clouds spit rain that looks like ''a gray woolen join between the land and the sky.'' Here, in this dreary landscape, Ida happens upon the aptly named Midas Crook -- a young man so devastated by his family history, he filters the world through a camera's lens. He's trying to photograph a rare shaft of light when Ida startles him. Despite -- or maybe because of -- her...