Not sure what the methodology is here, but I think it’s some combo of popularity and likelihood the book is finished, which implies length, dry-ness, as well as

Not sure what the methodology is here, but I think it’s some combo of popularity and likelihood the book is finished, which implies length, dry-ness, as well as “difficulty.” The thing I learned from it is the Hawking Index. Link copied here: https://en.wikipedia.org/wiki/Hawking_Index https://en.wikipedia.org/wiki/Hawking_Index I can’t find an updated version of the list