I have read a lot of books about the subject of Rennes-le-Chateau and considere myself as very critic when we know the bad quality of most of books.
Unfortunately, the Web of Gold, for most of its content, is not that good. It states that the treasure of RLC is the lost treasure of the Temple of Jerusalem, the same way as some people in the past declared that it was the lost tomb of Jesus. From one to the other, I prefere not to chose any.
The second part of the book is more interesting since it deals with more sure facts, like the life of Pierre Plantard de Saint-Clair, and we learn a lot about the craziness that took RLC since the 1960s.
But here again, the authors subjectively judge some facts and present them as the "most" possible, which is far from being true. I would for example quote the fact that the Martinist Order know where the location of the treasure is. All this ... waste the otherwise good parts of the book.
Anyway, it worth reading it since some never release information that can be trusted are presented there.
But the readers should keep themselves very prudent in believing anything in that story that does not have any source.