“The Storied Life of A.J. Fikry,” by Gabrielle Zevin is a hard book to describe. It is at once heartbreakingly sad and airily light. It is simultaneously weighty and ephemeral. It is undeniably sentimental, but it also kills off important characters with a sort of blasé shrug. It’s hardly even a novel; I would classify it, rather, as a novel-length short story, or perhaps a piece of young adult fiction written solely for adults. Above all, though, it is a pleasure to read.

Set in a small town on a tiny island off the snow-strewn, foliage-rich coast of Massachusetts, “The Storied Life” stars the prematurely curmudgeonly A.J. Fikry, a 30-something widower with few friends and fewer customers at his independent bookstore. “Island Books,” the store is called, where “No Man Is an Island; Every Book is a World.”

The reader meets A.J. while he is still mourning and deeply depressed, tearing into a young publishing rep and causing her to flee his store, crying. He then proceeds to get drunk, remove from a safe his most priceless possession — an original edition of Edgar Allen Poe’s earliest work, “Tamerlane”— and promptly pass out. When he wakes up, “Tamerlane” is gone. One would think this would finally drive the miserable A.J. to suicide, but, instead, he inexplicably starts exercising again, going for long runs and leaving the door to his store/apartment unlocked. (After all, what’s left to be stolen?) One day, A.J. returns through the open door to find a crying baby on the floor of Island Books.

When, two days later, the child’s mother washes up dead on shore — suicide — A.J. decides to keep the baby. Maya, as she is called, is a startlingly precocious child — the perfect companion, it turns out, for the misanthropic and endearingly pretentious bookseller. She grows older; he grows older. They laugh together, cry together, and all that jazz. A.J. finally starts dating again. And everyone — every single character — reads a lot.

At its core, “The Storied Life” is about books. Books and authors and reading and writing and publishing and rereading. Early in the novel, the reader is treated to the main character’s rant about his personal preferences (which is too awesome not to reprint and follows in abridged version): “I do not like postmodernism, post-apocalyptic settings, postmortem narrators, or magic realism. I rarely respond to supposedly clever formal devices, multiple fonts, pictures where they shouldn’t be — basically gimmicks of any kind…I do not like children’s books, especially ones with orphans, and I prefer not to clutter my shelves with young adult. I do not like anything over four hundred pages or under one hundred fifty pages. I am repulsed by ghostwritten novels by reality television stars, celebrity picture books, sports memoirs, movie tie-in editions, novelty items, and — I imagine this goes without saying — vampires.”

A.J. prefers short story collections; Maya likes classic fiction. A.J.’s police chief friend is partial to detective stories; the matronly women who give the hapless A.J. parenting advice prefer books with the word “wife” somewhere in the title. A.J. loves J.D. Salinger and hates David Foster Wallace. He has a complicated relationship with Edgar Allen Poe.

Every chapter begins with A.J.’s personal take on a famous short story (by the likes of Roald Dahl, Flannery O’Connor and Raymond Carver, to name just a few). And this gets at the heart of my one insight about “The Storied Life”: It’s not quite a novel. It’s something, but it just doesn’t read like a novel. To me, it reads like one of the short stories that A.J. so loves and that begin each chapter. It’s lyrical, and every end is tied up a bit more neatly than it would be in a novel. The storytelling is straightforward and descriptive, yet it’s not overwhelming or daunting in the manner of the hated Wallace. It’s charming. It’s almost like something O. Henry would’ve written, except twenty times as long.

Then again, the author, Zevin, has almost exclusively written young adult fiction in the past, which is perhaps why the sadness of her characters seems, at times, shallow and too easily resolved. As I said, “The Storied Life” seems almost like young adult fiction for an older audience — the earnest tone, the neatly solved mysteries, the coming-of-age narrative for everyone involved.

Above all, “The Storied Life” is the kind of book that makes you think about the kind of book it is. You dwell on your own literary preferences, the kind of books you would purchase for your own independent bookstore. It is, in the end, a romantic ode to the act of reading itself.