I recently upgraded from High Sierra to Mojave, and consequently iBooks became Books. I now have an issue with Books which was not present in iBooks.
I have stored many PDFs iBooks. Clicking on one of them and Preview opens. I could search in the text by Search; just fine.
Now in Books the Search in Preview gives "No Results Found" : for many PDFs but not for all PDFs. It works sometimes. (Of course I have checked that the text is present in the PDF.)
Thanks for your time.
Books version 1.16., macOS Mojave 10.14.2, MacBook Pro 13 inch Late 2013