Knight Fall is a murder mystery set in the SCA, Society of Creative Anachronism, a society for people who like to play at living in the Middle Ages.
The detective part of the book works well, but no more than that. I am not sure I would recommend this book to mystery buffs. I would, however, recommend this book to all people who are interested by the SCA. All the weirdness and fun that is the SCA is aptly described in this book, from the Great Dark Horde, the "motorcycle gang" of the SCA, to the rivalry between SCA fighters and SCA historians. Don't take the book to seriously, though - this is one person's vision of the SCA, and it probably does not hold true for all. I have been a member of SCA in Sweden, though, and I had great fun reading the book.