Thanks for the document size clarification.

By "cultural tradition", I'm talking of a literature which would be generally familiar to a population, or perhaps to its literate class.

Books and stories contribute not only knowledge or entertainment, but a shared knowledge and common metaphorical or conceptual language. And these need not be written traditions. I could reference, say, Psy's "Gangnam Style", Harry Potter, the Marvel Cinematic Universe, the Black/Blue / Yellow/White dress, Michelangelo's David, or Pikachu's face, and ... at least a large portion of readers would share that understanding.

If I were to reference instead, say, Sutro's "Affected", Hamilton Holt's "Commercialism and Journalism", Dersu Uzala, my uni flatmate's bronze torso, or the Vuck I'd spotted on a roadtrip some years back, there'd be a far smaller awareness of each.

There's a difference between information that's preserved, and information that remains culturally significant. Moreover, if the knowledge is considered to have both an explicit (book-transmissible) and tacit (experiential) component (think the difference between your chem book & lecture, and the lab section), what happens when the experiential knowledge dies?

What's the minimum requirement for knowledge to be considered live, in the sense that there's a community of practice which can sustain itself generationally?

I'm fairly familiar with counts of books and other types of records:

- US Library of Congress: ~40 million books (includes 15.5 m unclassified), 131 million unclassified records. Records > 400k new copyrights/year. Of these, there were > 800k research requests from Congress and other agencies, and ~360,000 items were circulated. Note that that last is > 0.1% of the total books, and 0.2% of the total holdings of the library. Data from 2020: https://loc.gov/about/general-information/#year-at-a-glance

- University of California Library System has a total of 40.8 million print volumes across 100+ libraries system-wide.

- Bowker, the US ISBN registrar, was issuing about 300k "traditional" and on the order of 1 million self-published ISBNs annually through most of the 2000--2020 period best I can tell. (These data used to be more readily available.)

- Total book publishing revenues in the US are about $25 billion. Assuming $10/copy, that's about 2.5 million copies, or about 7.5 books per person.
https://publishers.org/news/aap-statshot-annual-report-book-...

- Data on sales by specific title are ... hard to obtain. But I'd suspect that the top-10 title account for a large fraction, and the top-100 probably a majority of total sales. (Anyone inside Amazon know numbers?)

- Of copies of individual books ever printed, The Bible appears to be first, with an estimated 5 billion copies. It's trailed by the Quran (~800m) and Quotations from Chairman Mao Tse-tung (estimates vary widely from 800m -- 6.5 billion. It's interesting to note that all three of these are literally propaganda, two in the original religious sense, the third in the more modern ideological one. Six novels are thought to have sold over 100 million copies: A Tale of Two Cities, The Little Prince, Harry Potter and the Philosopher's Stone, And Then There Were None, Dream of the Red Chamber, and The Hobbit. https://en.wikipedia.org/wiki/List_of_best-selling_books

A friend who'd dropped out of a maths PhD programme once described the culture as "studying some specialised field in which there might be five or six other people in the world who could understand what you were doing." And finding this somewhat less than satisfying.

And I've had the exerience myself of studying lesser-known works and topics, or even some well-known ones, and finding that, variously, there was considerable insight to be found, or that what was widely "known" about a work ... didn't adhere closely to the work itself. To what extent then can the cultural awareness be said to be accurate.

Not sure if this makes my meaning clearer, but again, with an archive of millions to tens of millions of works, or even multiple copies of some smaller count, and much smaller pre-industrial populations of whom a small fraction were literate ... the living knowledge of those works must have been much smaller. At 7.5 books per year, an adult might read some 450 books in a lifetime. If half of those are popular, then the popular common canon is on the order of 200 works. What this figure might have been in ancient India I don't know, though for some cultures (Greece and Rome, and even 19th century Britain), knowlege of the Illiad and Odessey might have sufficed to be considered literate. Two books from a much larger accumulation.