there are some significant differences between the show and what happens in the witcher 3 and yeah i've not read the books i wouldn't read them if i was paid to do so, the author comes across to me as an arrogant dick, so i'd rather read fan fiction than his own books. but i just don't read books, its not something i do, i do most of my reading on here, reddit other forums, thats enough reading for me. I'd say if i were going to read a high fantasy story i'd start with LoTR first, but i just couldn't get into those books they are far too long winded for me. i've heard the witcher books aren't much different in that sense. but i've also heard that the books end before the beginning of the first game, so the games essentially pick up where the books end.