While searching for the earliest map of Antarctica, I heard about the Piri Reis Map of 1513 and the Oronce Fine (Oronteus Finaeus) Map of 1531. And in due course came across this book. I had my reservations, based on some of the info I had read, about Hapgood (as well as the Map librarian at LOC telling me he was a nut), but I feel that in this book he makes an interesting case for his hypothesis of an early seafaring/map making culture(s). Many of his theories about the maps he and his students examined are backed up by other experts and even military cartographers. Yet after digesting what I'd read a little more and reading "The Piri Reis Map of 1513" by Gregory C. McIntosh [see my review], Hapgood makes a number of assumptions and, at times, disregards or distorts evidence in order to better make his case. I think my lack of prior knowledge in this area made it more believable. Also, even though this book contains a lot of cartographic and mathematical descriptions, it is still quite readable for the average person. Finally, this edition (1966) could have had better (in color and sharper) pictures of the maps.