Another couple of ways (not using iTunes) are iFunBox & iMacSoft.
iMacsoft's "
iPad to PC Transfer" (versions for botheWindows & Mac) cost $19 US. This is my preferred method.
iFunBox is free (also has both Windows & Mac versions). Good at the price but IMO iMacSoft's SW is better & easier to use.
You can move books (&other files) both ways, from PC to iPad & from iPad to PC. Easy to move them in batches or individually.