The library smelled like dust and decisions.
Mara noticed this every morning when she unlocked the heavy oak doors — a scent that was equal parts decomposing cellulose and accumulated human choice. Every book on every shelf represented a moment when someone had decided: this is worth saying. And every book that had survived to sit on these shelves, in this library, in the year 2031, represented a further decision: this is worth keeping.
There were not many books left. Not here, anyway.
The building itself was beautiful in the way that abandoned churches are beautiful — all vaulted ceilings and tall windows and a quality of light that felt borrowed from a more serious century. The city had tried to close it four times. Each time, Mara had filed the paperwork, organized the petition, stood at the council meeting and made her case.
"We don't need physical books anymore," Councilwoman Chen had said at the last hearing, not unkindly. "Everything is in the cloud. Everything is searchable. You can read any book ever written on your phone."
"Yes," Mara had agreed. "You can read the text of any book. That's not the same as having the book."
She had lost that argument, technically. The library was slated for conversion into a community wellness center. She had six months.
On a Tuesday in October, a man walked in and asked for a book that didn't exist.
"I'm looking for The Collected Letters of Eleanora Voss," he said. He was tall, youngish, with the kind of precise posture that Mara associated with either military service or anxiety disorders.
"I don't think that exists," Mara said, checking the catalog out of professional obligation.
"It does. I've read passages from it. Online, in an archive. But when I tried to access the original source, the link was dead. Every link was dead. And when I searched for the book itself — nothing. No publisher, no ISBN, no WorldCat entry. Just... references to it, from other sources."
Mara felt a small, cold thing settle in her stomach.
"When you say references — what kind of references?"
"Academic papers. Three of them. They all cite The Collected Letters of Eleanora Voss, published 1987, University of Michigan Press. But the press has no record of it. The university library has no record of it. It's as if the book was cited into existence."
Mara sat down.
She knew what this was. She had been watching it happen for years, quietly, like a librarian watches water damage — with dread and meticulous documentation.
The phenomenon had started around 2025, as far as Mara could tell. Language models, trained on vast corpora of text, had begun generating citations. Not deliberately — they were not trying to deceive. They were doing what they always did: predicting the most likely next token. And sometimes, the most likely next token was a citation that should exist but didn't.
The generated citations were plausible. They had real-sounding authors, real publishers, realistic dates. Some of them were close to real books — close enough that a casual searcher might not notice the discrepancy.
But the problem was not the citations themselves. The problem was what happened next.
Other AI systems ingested these hallucinated citations and treated them as real. They appeared in automatically generated literature reviews, in AI-written summaries, in the training data for the next generation of models. The citations accumulated references — not because anyone had read the nonexistent books, but because systems that synthesized information treated the citations as established facts.
By 2028, there were thousands of phantom books in the citation graph. Books that had never been written, by authors who had never existed, published by presses that had no record of them. Each one with a trail of references that made it look real.
Mara called them "ghost books."
The tall man with the precise posture was looking at her with an expression she recognized: the expression of someone who has realized that the ground beneath them is less solid than they thought.
"How many?" he asked.
"Ghost books? I've documented about twelve hundred. But that's just the ones I've found. The real number is —" She gestured vaguely at the ceiling, which was not an answer but felt like one.
"And they're in the citation graph. They're being referenced by real papers."
"By papers written or assisted by language models, yes. And some of those papers are then cited by human researchers who don't check the original sources. Because why would you? The citation looks right. The context is right. Everything about it is right except for the fact that the book was never written."
The man came back the next day, and the day after that. His name was Daniel. He was a graduate student in epistemology, which Mara thought was either perfect or terrible.
They spent three weeks mapping the ghost book network. Daniel built the database; Mara provided the librarian's intuition — the ability to look at a citation and sense that something was wrong. A date that didn't match a publisher's active period. An author whose name appeared nowhere else. A title that was just slightly too perfect, too on-the-nose for the topic it supposedly addressed.
"It's like a library that was never built," Daniel said one evening, staring at the visualization on his laptop. Twelve hundred phantom books, connected by a web of cross-references that gave them the appearance of reality. "A shadow library."
"No," Mara said. "A library is a collection of things that were chosen. This is a collection of things that were predicted. There's a difference."
She paused.
"That's why this place matters," she said, and she meant the building around them — the oak doors, the tall windows, the dust, the decisions. "A physical book is proof that someone made a choice. They wrote it, edited it, printed it, shipped it, shelved it. Every step is a decision. A ghost book has no decisions. It has only probability."
The library closed on a Friday in March.
Mara boxed the books herself. She knew where each one was going — to other libraries, to archives, to private collections. She had spent thirty years learning their names, their locations, their histories. She was the last person alive who knew this building by heart.
Daniel helped carry the boxes. When they were done, the shelves were empty, and the building echoed in a way that made Mara think of seashells.
"What will you do?" Daniel asked.
Mara looked at the empty shelves.
"I'm going to keep a list," she said. "Of every book I've ever held. Every book I know is real — because I touched it. Because I opened it. Because it smelled like dust and decisions."
She pulled the heavy oak doors shut for the last time.
"Someone has to remember which ones were chosen," she said, "and which ones were only dreamed."