This book had a slow start plot wise and I felt a bit impatient for the real action/adventure to start but once things got underway, it became a better read. I definitely felt what happened to be its quite unlikely but thats kind of to be expected in such a book, to an extent I suppose. Hence I wouldn't recommend it to sceptics. It is very much Indiana Jones-esque in terms of the settings and plot. I quite enjoyed the historical aspects of it - I'm not entirely sure how much is fictionalised but in either case I was intrigued by the talk of previous adventurers coming across the cave area and so on.
I found the text quite readable once the real action/plot got underway, by approximately page 45. Prior to that, there was too much emphasis on the personalities of the various characters and an element of one-upmanship, that sort of thing. The text is quite dialogue heavy and while there are descriptions of the various places the characters end up in, these aren't in any way excessive. I suppose part of the tension or thrill even is in trying to picture the finer details - in imagining yourself in the protagonists shoes, or in those of one of the other main characters.
I liked that some pages consisted of photos captioned with what the photo shows, mainly of places mentioned in the text, in earlier adventurers writings and so on. It helped me to imagine the environments described in the text - well, moreso the surroundings - the images mostly (certainly at the start) show the rocky caves from a distance - things like that.
In the end, it wasn't quite what I expected (I won't elaborate so as not to give any spoilers, although I would say its less science fiction related) but I did enjoy it as a fairly light read. It isn't an excellent read, with a bit too much focus on personal, petty issues and I felt an element of not great credibility due to some sub-plot details but I found it, once the plot got proper underway, quite a good escapist type read. It was a bit long winded towards the end bt overall its not a hard book to read, with a reasonably good flow and it also has short chapters, so in those respects its a relatively appealing read.