When writing about the books of Susan Orlean, it’s hard not to feel like the neurotic Charlie Kaufman character in the film “Adaptation,” sweating in front of his typewriter as he tries to work on a screen adaptation of Orlean’s “The Orchid Thief.” He worries that her book is too sprawling and bountiful to cram into a contrived Hollywood plot, and he ends up just thinking about the banana nut muffin he wants to eat. Orlean’s work in general has that elusive quality to it: exquisitely written, consistently entertaining and irreducible to anything so obvious and pedestrian as a theme.

Even Orlean herself, a longtime staff writer for The New Yorker, admits to feeling overwhelmed by her idiosyncratic vision; her newest volume, “The Library Book,” almost didn’t happen. “I had decided I was done with writing books,” she writes. “Working on them felt like a slow-motion wrestling match.” But after moving to Los Angeles seven years ago, around the time her book about Rin Tin Tin was published, she learned that the city’s Central Library had suffered a catastrophic fire in 1986. The discovery nudged her into the ring again.

“The Library Book” is about the fire and the mystery of how it started — but in some ways that’s the least of it. It’s also a history of libraries, and of a particular library, as well as the personal story of Orlean and her mother, who was losing her memory to dementia while Orlean was retrieving her own memories by writing this book. Orlean recalls a library-centric childhood in suburban Cleveland, when her mother would let her wander the stacks on her own. “Those visits were dreamy, frictionless interludes that promised I would leave richer than I arrived,” she writes. “In the library I could have anything I wanted.”

That sense of possibility animates her new book, which is a loving tribute not just to a place or an institution but to an idea. “The publicness of the public library is an increasingly rare commodity,” Orlean writes. “It becomes harder all the time to think of places that welcome everyone and don’t charge any money for that warm embrace.” That turn at the end of the sentence is pure Orlean; even when contemplating something as big and abstract as “publicness,” her sensibility veers toward the immediacy of the human touch.