I just bought The Witcher from GOG and found that there was a downloadable extra called "The Witcher Story". Is it something I should read before playing to better understand the situation at the start of the game, or something spoiling that I better leave be until I've finished the adventure?

Well, it will spoil you the cutscene intro. On the other hand, you'll be able to see how true to the book (that's the first short story of the Witcher book series) CDP stayed when recreating that. Other than that, no spoilers, but I'd say insight it offers for personalities of Geralt and some minor characters' you'll meet later in the game might be interesting.

Doesn't really spoil the game -- Its the first story from the first book of The Witcher. None of the Witcher books will spoil this game or TW2, since the books chronicle Geralt's life until he gets killed in battle, and the game happens roughly five years after that when he somehow comes back to life.

Definitely read it first. It will set the tone quite well, and part of it is even shown again in the intro cutscene, so it's actually relevant to the game's story. I'm pretty sure the developers intended for you to have read it first.

Plus, it's the very first Witcher story ever so you don't have to worry about it spoiling the novels or anything.

IThanks!

Not to bitch, but I hope that part were you wrote that Geralt already had died wasn't spoiling anything either.

This amnesia plot seems interesting. I liked it in Planescape: Torment and STALKER: The Shadow of Chernobyl and I'm sure I'll like it in The Witcher too (and maybe Sanitarium, another game I've bought from GoG but haven't played yet).

Well it sort of spoils the end of the novel series, but Geralt's death is mentioned within the first 15 minutes of gameplay and then again several times during the game, in one point even describing how it happens, so I don't think anyone in the forum for The Witcher game would feel angry about that :P

Also only two books from the series are available in english as of now (third one to be released next year it seems), so its not like most people here can easily get the books and read them shall they want to.

No harm done, then! =)