I made a thread poll awhile back asking if I should get a kindle paper white or a regular kindle. Got a paper white not too long ago and started reading The Witcher books. Im half through the first book and digging it a lot. Its surprising to see how good of a job CD Project RED did translating the tone and atmosphere of those books into those games. Can't wait to read the the initial series and start a new play through of the Witcher 1-3 with a new perspective!
I am actually in the midst of doing exactly this right now. I read all the books within the past couple months and then began a full series playthrough. It'll be my second playthrough of each game and the first time playing them one right after the other and obviously first time after having read the books. I'm on the Witcher 2 at the moment.
It was very interesting playing the first game again for many reasons. For one, it the first time I've played it with the foreknowledge of the sequels, and it certainly feels even rougher now than it did the first time since I know how great 2 and 3 are. It was also very interesting playing it after reading the books, for both good and bad reasons. There're a ton of references and callbacks to stuff from the books that I really enjoyed, but there are also several decisions they made with the story and characters that kind of rubbed me the wrong way.
It really made me wonder what fans of the books thought of the first game back when it originally came out, because if I didn't already know where CDPR takes things with 2 and 3 and how well they pull everything off, I think I would have been very disappointed with the game from the perspective of having just come off reading the books.