The books are really easy to read, there's not pages and pages of lore, and it feels pretty quick-paced. My local library had them all. You may feel taken aback, wondering what the hell happened in between some of the books, but that's just the style of the author, really focusing on some events, rather than a biography of the Witcher.
I did read them some years ago, but i remember having enjoyed them.
You don't need to read them to play the game, though you'll notice some more details if you have. And playing the game may answer some of the questions you had asked yourself when reading the book.
Overall, combat system is pretty easy, you just have to mix potions in a bit, and the difficulty is pretty decent. I used to always stock potions till the last boss, and wonder why i did, but in this case, i actually used them during the entire game. There's no "class" system though, and we all play the exact same character, with the exact same playstyle, so replayability is a big no from me, even if you'd want to see what would have happen had you side with another "faction". It would have been too repetitive.
Still, the main good point is... you're a witcher, all humans seem to hate you, all girls seem to want to have sex with you, and you definitely feel being a stronger being. Puny humans.
I hated the fact that i sometime had to run from point A to point B to point C to point A to point D, but if you enjoy the scenery and the scenario, then it's playable. Though Witcher 2 is definitely better than Witcher 1, in my opinion. If you have time, still play the first one, for the good story.