This book is one of a number by french author Gerard De Sede. It is a follow up to his earlier book the accursed treasure of rennes le chateau (also known as L'or du rennes). In this newer book he updates his theories regarding the rennes le chateau affair and analysis the efforts of other authors. It is on the surface a interesting book and seems to offer an authorotative overview of the better known theories. There are however a number of issues. To begin with there is considerable speculation that although the author of his previous book he was told what to put in it by the now debunked priory of sion (Well debunked for most people. Some do still believe there may be something more to them). Although there is no proof that this has happened a second time, the possibility cannot be ignored. At times he refers in the book to "we" and at other times uses single references. Another problem are the mistakes, sometimes ridiculously basic that have slipped into the book. One example is in a chapter dealing with The Holy Blood and the Holy Grail. In which he refers to the three authors, Henry Lincoln, Michael Baigent, and Richard Leigh as three English authors. Anyone who has ever glanced at a copy will realise that this is untrue. Only Henry Lincoln is English the other two come from America and New Zealand. It may only be a minor error but it is one amongst many. Too many to take the book seriously. It does have it's good points. But poor checking of facts leading to silly errors from a man who really should have known better lets this one down.