A "better" index differentiates between passing mentions and substantive discussions.
If you download a book with a flat or missing ToC:
Google often throttles these searches. Try: index of epub books better
For those who prefer command-line interfaces, Python is your friend. Libraries like ebooklib and pillow allow you to write a script that:
Sample Python logic:
from ebooklib import epub
import os
for filename in os.listdir("/your/epub/folder"):
if filename.endswith(".epub"):
book = epub.read_epub(filename)
title = book.get_metadata('DC', 'title')[0][0]
author = book.get_metadata('DC', 'creator')[0][0]
print(f"| author | title | filename |")
Redirect this output to a Markdown file, then convert to HTML. You now have a text-based index that is easily searchable via Ctrl+F.
A hidden index is useless. Ensure it appears in: A "better" index differentiates between passing mentions and
Calibre is the industry standard (free and open-source). It turns a messy folder into a searchable, sortable index.
How to index your books better with Calibre: Non-Indexable Content: