The book's claim to alternative status mostly revolves around a critique of outdated archaeological texts about the Maya and the author's effort to argue for placing the Maya among the most advanced premodern civilizations. O'Kon is especially dismissive of the idea that the Maya were "Neolithic" because he reads this as "primitive" rather than its more specialized meaning of lacking metal tools. This isn't terribly controversial, except perhaps where he trails off into speculation about whether the Maya's four-cornered mythic cosmos can be related to the modern space-time continuum of physics. He also seems more dismissive of the Olmec inheritance used by the Maya as a springboard for their culture, all the better to make the Maya seem as though their achievements were all the more astonishing for lacking clear antecedents.
The book's most sensational claim is that several Maya buildings, including the tallest towers, were cast in place from cement, a theory O'Kon has been researching and reporting on for decades. His discussions have appeared in the anthologies System-Based Vision for Strategic and Creative Design (2003), Environmental and Water Resources (2007), and J. Douglas Kenyon's Forbidden History (2005). I am not an expert in Maya construction, but this seems to be a bit of an exaggeration from the truth that Maya buildings had an external layer of fitted stone within which was a cement-like fill, which isn't quite the same as prefabricating a building wholesale from interchangeable parts. It is also unfair to call Maya pyramids "high rise" structures, since this implies that they had multistory living spaces; instead, they were large platforms built by accretion over time. In my cursory search about the cement, I can't find much information about cast-in-place Maya concrete except what O'Kon has himself written.
I'll try reading a bit more of the book, but it's looking like that's about the extent of its alternative claims.