The Rough Guide to The Da Vinci Code is a well-written, well-researched and serious investigation into the issues, themes and history raised by Dan Brown's thriller. I cannot rate it highly enough -- it is more than just a companion to The Da Vinci Code, it is a worthwhile work in its own right, a highly useful compendium of information on Gnosticism, Early Christianity, ancient history, goddess-worship, the Holy Grail, the Cathars, the sacred feminine and so on. Amid the plethora of silly books and outright rubbish concerning The Da Vinci Code, this Rough Guide stands out as a major and valuable contribution. The publishers and authors are to be congratulated.