How to enable text search of ePub files, in the SumatraPDF reader…
1. Go to: top left corner icon | Settings | Advanced Options.
2. At the top of Sumatra’s config file you’ll see:
3. Change false to true. Save and exit.
Mostly you’ll be sending an ePub over to a mobile device, where it will be handled by better apps. But the choice of reader is limited on the Windows desktop where you may also be archiving the .ePub files, and where you may want to sometimes hop into one of the files to swiftly find a specific name or title.
I don’t yet know of desktop freeware that can search across and inside of multiple .ePub and .mobi files.