The official strategy guide has two versions with one being a regular release while the other is a collector’s edition. The latter comes in a premium hardcover in addition to having 32 extra pages of art and a 96-page compendium. If you are interested, you can buy the two versions of the guide with the following links on Amazon: The Witcher 3: Wild Hunt Collector’s Edition: Prima Official Game Guide and The Witcher 3: Wild Hunt: Prima Official Game Guide.
The other new book released is The World of Witcher, which includes more lore on the people, locales and other elements from the universe. You can check it out here.
The Witcher 3: Wild Hunt is a massive open-world RPG based on a series of Polish books. If the sequel is the first game in the series you will be playing, you may get lost in the storyline and/or gameplay. Thus, you might want to check out the two official strategy guides in addition to The World of Witcher.