The official website is
http://queensblade.net/The books are based of the Lost Worlds battle system. "Play requires two players and at least two "visual combat books", with each player choosing a character (i.e., a book) from those available. At the start of play, each player removes the character sheet for that character from their book and hands the book to his or her opponent. The character sheet lists the various combat actions which the character can take during the battle. The combat book lists the effects of the attacks in tables, and serves as a visual reference for what the other player is doing. Hence, each player views entries in the book from a first-person perspective, seeing only their opponent and not themselves."
http://en.wikipedia.org/wiki/Lost_Worlds_(gamebook)
The story from the website (the babel fish translation...is really bad):
In 4 years which decide the queen of the country competition meeting of the life 懸 [ke] of one time, [kuinzubureido]. The strongest woman can control this country in accordance with the tradition which continues from building country. If it is the woman of 12 years old or more, if even if, not being the human also, it is the woman of the intellectual living thing even with the person of the foreign country, it can recognize participation. As for competition meeting rule needless murder being agreeable. It becomes the tournament of the life 懸 [ke] which freely used the weapon and the homicide skill which oneself makes proud. On the one hand until it plays abandons, or stops being able to move conclusion is not attached. And pattern of fight is relayed to the crystal sphere of all country by the magic of the court magic teacher. As for the populace the fight is observed feverishly. You are the woman fighting loyal retainer who participates in [kuinzubureido]. As for the destiny which expects the seat of the queen or humiliation of defeat, or death?
They are making an anime series. I mostly buy the books for fun. I don't play with them.