Also in my several posts in the link below:
Transfering book (or many books at once) wirelessly using any free apps with wi-fi capabilities.
or
Transfering over USB using Goodreader app, without iTunes
https://www.mobileread.com/forums/sho...d.php?t=262985
Wireless transfer using Safari browser and Calibre content server
or
Using USB memory stick and HDD, with or without jailbreaking
https://www.mobileread.com/forums/sho...3&postcount=14