Here are a few thoughts on the book’s writing style. I am not a writing expert, nor a linguist, just a discriminating reader.
In the book I sensed three distinct writing layers (for want of a better term) The strategic plot dealing with the catholic church, the secret society 'Priory of Sion,' and da Vinci's art are well thought out, very thoroughly researched, and provides very juicy historical and religious fact-based placement. This is what makes the book 'gripping' – the ability to smoothly intertwine fact and fiction. Overlaid onto this solid foundation is built a very amateurish tactical plot (descriptions of the characters, who runs where, who dies, how, why, etc.). The filler material (general descriptions, small details, nuances, jokes) was simply juvenile and bordered on silly. Pithy jokes about Rudy Giuliani (for eg.) were definitely out of place here.
The inconsistency in depth and style of writing leads me to believe that this author hired ghostwriters as many others do – (google 'ghostwriters') The author probably did a lot of research, laid out the main plot, outlined how the story should unfold and penned segments associated with the main theme. Then the ghostwritiers came in and “filled-in” the book. The author likely reviewed the entire copy, and made changes. This is the only way I can explain the complete disconnect with the different 'layers' of the book. As some of you are currently reading this book, or have already read it, I would love to hear your opinion on this.
If I were to read another of his books, I would subconsciously use this template and update my analyses. Thus I try to avoid follow-on books of bestselling authors. They fit a pattern. Once you sense it, then you hate it! Overall, a great fiction read! Highly recommended, except if you have upcoming exams, deadlines or pregnancies due! If you are looking for literary classics, try Hemmingway, or Maugham.