> I noticed that the book was very carefully referenced with detailed end-notes, some like mini-essays with references to papers by a wide range of authors. These notes comprise about a third of the word count of the book.

This is standard for most books written by academics as they are usually a compilation of their published and unpublished prior work.

Of the last three non-fiction books I read two were 1/3 references, the third book I’d consider more like long form journalism rather than an academic work.

The current book is 1/3rd references by page count and about 1/5th notes at the bottom of the pages.