Finder is not finding my books on the mac I am trying to sync my books from my mac to my iPAD but the finder is not showing my books so nothing is synced. 

Even PDF files are not showing in the finder. 
I am using MacOS 10.15.3
The best way to sync your books across Apple devices is using Books app. Just tested on the latest versions of macOS &amp; iOS, and it works perfectly.

So, you need reproduce the next steps:


Open Books app (Spotlight Search -> type "Books" -> If needed, log in)
Drag and drop your .pdf, .epub or other file
Done. Your book is available across all devices where you signed in