With his sixth novel and ninth book, Nicholson Baker proves you just can’t pin a good writer down.

Baker made a splash in the early ’90s with his naughty and readable “Vox,” about phone sex, which he followed up with the lyrical and funny “U and I,” about his obsession with John Updike — sort of a “Roger and Me” for the Lit set.

He also has written a children’s book, “The Everlasting Story of Nory,” and published a collection of essays, “The Size of Thoughts.” Last year, he won the National Book Award for nonfiction for “Double Fold,” a dashing and angry polemic on the destruction of American newspapers by librarians who follow the cult of microfiche.

None of which prepares you for “A Box of Matches,” a witty slip of a book about a man and his fireplace.

Emmett, an editor of medical textbooks, has a wife, two kids, a cat, a pet duck and a lovely colonial house with four enormous fireplaces. He is 44 and content, but for one thing: He wants to think. After a New Year’s trek to watch the sunrise, Emmett resolves to indulge his pensive bent.

He wakes about 4 every morning, takes one match from the box and lights a fire. Tucked in a chair while his knees warm in the blaze, Emmett travels through the majestic ordinariness of his little world. He ruminates on making paper airplanes, the morning mist rising from a yield sign and whether the duck is warm enough in her outside pen. Thoughts spill out in Baker’s aphoristic prose: “The fire is like a cheerful dog that waits by the table as you feed it life-scraps.”

It all sounds ridiculously mundane — no angst, no disaffected railing, not even a whiff of David Lynch-style hidden perversions. So why does it work like a charm? Because Emmett is charming and whole and funny and wise. Because Baker is a literary Rumplestiltskin, spinning gold out of the straw of the everyday: “I’m always happy to open a dishwasher,” Emmett says to himself, “curious to see what Dead Sea Scrolls await within.”

In a passage about a trip to the gas station, Baker captures the small, stupid joy we feel when we hit an amount — $16 and no cents — bang on, without having to click, click, click to a whole number. “Bingo, baby!”

Baker glides as easily to the profound, with observations on a parent’s unexpected grief at his boy’s growing too big to have his hair washed for him — “the loss is enough to make you lose composure” — or a son’s heartbreak at his father’s encroaching dementia.

Like his earliest novels, “The Mezzanine” and “Room Temperature,” Baker’s newest book is a grand work on life’s minutiae, as warm and glowing as the embers in Emmett’s fireplace.