I think that in any case about mostly anything people want to compare and contrast two things simply for the fact that they know more about one thing over another. Also given that these two cultures happened at a somewhat similar time and had such rapid expansions and declines, inclines people to want to compare these two empires. Given that Conrad and Demarest were archeologists they felt that they could write a book with both of these empires in order to show the world what they learned through their archeological findings. 

Conrad and Demarest do put a lot of their faith in their archeological findings, however they also understand that they can only put so much faith in it “written accounts and archeological research, both sources of data have their limitations” (86). There will always be accounts that are misunderstood or even completely untrue an example of misunderstood “writings” would be, “the native Andean peoples never developed systems of writing, and all documentary accounts of preconquest history were compiled during the Spanish Colonial Era” 86). In the case of the Aztecs “Some of the distortive factors discussed above actually illustrate one of the major themes: the Mesoamerican obsession with legitimizing power through a prestigious heritage- the elite’s need to justify its rule through historical and mythical ties with the past” (17). Both of these groups have problems with information and yet there is so much that can be learned through different kinds of finds. Comparing any two groups has its own set of problems including sources.