I must admit upfront that I am not a fan of Dan Brown's Da Vinci Code (actually, I hated it) and so approached this book without enthusiasm. I'm happy to report that this book has more in common with Katherine Neville's The Eight than with Brown's book. For me, this is good news. 
 Mosse sets up more than a few challenges for herself. The narrative that switches back and forth between present time, the basic plot deals with over-used themes (Cathars, the Holy Grail, Catholic conspiracies, French cathedrals, etc), and the reliance on actual events is enough to warrant several long monologues to educate the reader on the finer points of such things as the Albigensian Crusade. It would be easy for the story to slow down to a crawl under the weight of all this and to her credit Mosse keeps the story moving. Yes, it is overlong in parts but not fatally so. A few plot points come out of nowhere making them feel like the result of poor editing. Other scenes are drawn out beyond what was needed to develop character, move the plot or even set the mood. 
 The heroine is smart and resourceful. In her former life she was even more resourceful, healing the sick and swinging a sword when the occasion calls for it. The male characters are either evil, weak or enthralled by an evil woman. It's a nice change of pace from the usual thriller set up where the women are weak and the men all powerful. The secret, or perhaps I should say SECRET, probably isn't as interesting as it should be for 500 pages of effort. It's also a bit too New Age for my taste but, let's face it, it's a McGuffin. 
 This book is enjoyable if you take it for what it is: well-written, escapist fun. When an author clues you into the reincarnated characters by giving them the same first 
 name in each life (Alais = Alice, William = Guilhem, etc) you either snort in disgust or go along for the ride. When the characters even LOOK the same as they did in a former life, well, if the best writers go too far on occasion. 
 Labyrinth is a better book that Da Vinci but not as good as The Eight. It's a fun read for a long airplane trip.