I have read (in detail) the four original Ellis books. Each one is fascinating in a different way, mainly because of Ellis' vaunted 'lateral thinking' mode.
Ellis posits that the Khufu (Great) pyramid is a map in stone of the world's landmass, and devotes a significant part of this book to a 'loner' quest to get as close to a supposed knowledge-vault at the base of K2 - delineated in the pyramid - as he can. This part of the book is akin to a 'go long' football throw.
(I have read a fair amount on pyramid theories, and - so far - the overall 'feeling' of the Khufu pyramid brought out in "The Giza Power Plant: Technologies of Ancient Egypt" by Christopher Dunn comes closest to my truth. I do not really believe in Dunn's actual 'power plant' mechanism, but his handling of the otherwise-obscure details of a 'purpose-built' pyramid rings very true. It is very emphatically not a tomb...)
To me, the real gem in K2 is Ellis' treatment of Alexander the Great. Alexander was an amazing man, who faced down one of the world's greatest (or at least most sizable) armies in it's own territory - and won, repeatedly. Then, rather than settling down into his spoils - one of the world's richest and most cultured countries - he basically took off into one of the planet's most barren and inhospitable areas: the ever-growing, mountainous foothills by the Afghanistan-Pakistan borders. (Interesting that Cheney/Bush,Sr patrols are scouting that region now, for you conspiracy buffs...) When he could go no further, only then did Alexander turn south into India.
Ellis does an excellent job of explaining this 'strange' behavior by weaving evidence that Alexander was actually on a purposeful quest to discover a 'God'-base or immortality-station disclosed by old-religion priests during his mysterious 'side-trip' to Siwa Oasis in Egypt. Since Alexander was obviously extremely intelligent and purpose-driven, he was unlikely to be 'rattling around' such an impoverished area with an entire Macedonian army. Ellis provides a plausible scenario for Alexander's presence there - and a good read, to boot.
(In my mind, the main question is whether the priests gave accurate information as best they could, or simply devised a plan to send Alexander [their conqueror] off as far away and long as they could...)
I recommend this part of the book highly, and look forward to any further facts coming to light on this issue.