The years, after they have raced by, drop their memories in heaps and piles, caring little for the kind of organization required to make proper sense of a life. For his third dazzling, graceful novel, writer Sam Savage, of Madison, Wis., illuminates this truth in a fictional stream-of-consciousness memory dump by an aging, unemployed, depressive protagonist. Remarkably, strangely, readable, "Glass" gives us both a life story told well and tantalizingly in unspooled snippets, and a thoughtful rumination on the nature of late-life reflection itself.

The text of "Glass" is meant to be, apparently, a manually typed, free-associated, memoir-slash-preface for a book. (Savage leaves many aspects of the story open to interpretation.) The writer of the preface is Edna, and the book in question is a new edition of the one celebrated novel of her late partner, Clarence. Edna intersperses her memories of Clarence in her daily activities, her struggles in continuing the "typing" (as she refers to her work), and her ambivalence toward actually continuing the preface. She visits a near-obsolete typewriter repair store, she reluctantly agrees to water her neighbor's plants and care for her rat, she muses on her solitary life of crossword puzzles and coffee, and eventually through brief anecdotes paints a picture of Clarence as a hack writer and faithless lover. Edna, alone now in a profound way, watches sunrises over the neighboring ice cream factory, ditches her landlord and most other social contacts, and appears to be coasting toward an unremarkable, solitary end.

"Glass" should be a tedious read and the first pages feel like the beginning of a long, high-fiber slog, but Savage's uncanny control over his material soon has the story pulling the reader in. The things Edna leaves out and the things she leaves until the end -- what happened to Clarence? Was Edna ever a writer herself? How does she support herself? Was the mysterious camp she refers to a writer's colony or an asylum of sorts? -- make this story of a sad old woman race by with a thriller's speed. As he's shown in his previous novels, "The Cry of the Sloth" and especially "Firmin," Savage can take a mundane or even off-putting idea and, with skilled and soulful telling, make it rise to exquisite art.

Note is usually made of Savage's age upon the publication of his first novel in 2006: He was 65. But the layers of wisdom, the rapier honesty and the sheer intellectual rigor he displays in novels like "Glass" argue that seasoning may well trump youthful audacity in writing, perhaps the most cerebral of the arts. And, surprisingly for someone who gave us the listlessly expiring Edna, Savage encourages us all to think and create and surprise as long as we are able.

Cherie Parker is a book critic in Washington, D.C.