The Lost Tomb - David Gibbins

I picked this up in an airport bookstore headed out on our recent vacation, and generally enjoyed it, but with some reservations.  First, the author's exposition style is clumsy - he has a great deal of background historical material he has to convey (all of which I liked) but he does it by having people just say it in completely unbelievable conversations, using words like "disgorge".  Reading along I could see better, more believable ways that the exposition could have been handled without destroying the veracity of the scene.  The end result is that you never are allowed to forget that the characters are not real people, but instead just mouthpieces for a plot, and they are constantly having to stop acting believably to spout off professorial dissertations to inform the reader what's really going on.  A related problem is the way characters inexplicably open conversations by talking in paragraphs about experiences from the prior book, and using words and phrases that people just don't use in ordinary conversations.  They may be thinking these thoughts, but this isn't what they'd say, and again, believability is lost. 
Second, the author has a real thing for underground archaeology, where divers enter a tomb or cave from underneath (since the site in question is usually inconveniently located under the center of a major city).  As well as the author writes (and it is good) it was always hard somewhat hard to visualize what was happening, and it strains credulity to believe that all these sites are conveniently accessible from underneath via some sort of tunnel or excavation.  After a while it becomes pretty clear that the reason they're accessible is because the characters have these really cool underwater suits, and the author is just looking for ways for them to use them.  When you're a hammer, every problem looks like a nail, I guess.
That having been said, I did generally enjoy the subject matter and the book, but again, with another minor caveat.  The overall theme is that there's a gospel written by Jesus personally, and it is of vast historic importance because it contradicts traditional church teachings (a good theme handled well in Steve Berry's The Third Secret).  The problem here is that the key teaching is - literally - the last two sentences of the book, which just aren't supported enough to really support the book, I didn't think.  Berry's Third Secret of Fatima is thin enough, designed as it is to conveniently contradict every major contemporary church teaching - but it is grounded enough in the plot throughout the book that when you finally read it it makes sense from a storytelling perspective.  This one looks a lot like a convenient deus ex machina.
But, again, I generally liked the book - maybe even more so because I started to get interested in how its shortcomings could be defined and fixed.  Guess I've been editing too long...