I don't normally use game guides as I believe it spoils the game for me by taking away the wonderment of discovery. BUT The Witcher 2 is not a normal game, and it has an immense amount of replayability value, and this guide really helps in uncovering the different paths you can take. Plus, I've already completed it on my own so I thought of using a guide on my second (and third, and fourth, and..) playthrough.
It has a lot of easter eggs, extra info such as pop culture references, references to books by Sapkowski, recommendations and tips on what to buy from merchants so you don't waste your hard-earned orens, detailed maps and locations, a comprehensive guide on creatures and items/weapons, detailed character background, well-organized quest progression guide, information on how to get passive abilities, consequences of taking certain paths and how it affects later parts of the game, and most importantly, interviews with the game developers! For such a low price for a book full of Witcher goodness, this is definitely a MUST-BUY for not only fans, but the general gamer out there.
The only downside to this book that I can think of right now is that there is no Collector's Edition Hardcover version of it. I will definitely buy that in an instant.