For those who are not really 'up' on their wild and wacky theories of ancient civilisations (that includes me), this is a good survey. It is immediately apparent that two hands are at work here - the book does not hang together and some key theories that take large sections of the book to justify, are doubted in single sentences in subsequent chapters.
That said, it is a most enjoyable read, and there are some genuine thought provoking points here. Namely, that intelligent man must have been around for an awful lot longer than the archaeological establishment would have us believe.
Another facsinating point, and one which deserves further study is the observations that Turkish portalans dating from over a thousand years ago, are better at mapping the world than any other map into the early modern age. They even show the Pacific coast.
Also, the observation that the land-mass probably under the Antartic ice shield bearing a similarity to a land-mass seen on several maps as being in the Atlantic ocean is intriguing, as is the seemingly plausible theory as to how it 'shifted' (possibly a realignment of the poles following a massive asteroid collision).
I also liked the research that attempts to show more than a passing similarity between various mythologies from around the world, however, the book looses credibility towards the end, when the authors attempt rather too heavily to convince us of the overarching unity of all this.
Nevertheless, if you have the money, spend it - its a good read!