Shlain seems to think that if he keeps throwing information at his readers, they will be impressed (or overwhelmed) by the wide-ranging research he must have done, and be convinced of his thesis. But all he's actually done is read some books by other people and present their sometimes controversial ideas as facts; this is the essence of sloppy scholarship.
A notable example is showcased on page 382, where there is a photo supposedly of "Chief Joseph of the Nez Perce." But it's not Hanmaton Yalatkik ("Chief Joseph"); it's a member of one of the Plains Indian nations, as can be seen clearly from his eagle feather headdress (the Nez Perce were not Plains Indians). If a picture is worth a thousand words, what is the worth of a picture with a wildly innaccurate caption?
Toward the end of the book he discusses EEGs, which measure brain waves. The dominant brain wave when reading a printed page, he tells us, is the beta wave, while the dominant wave when a person watches TV is the alpha wave. But there's another activity where the dominant one is the alpha wave: meditation. Here he's clever, because he never equates watching TV with meditating; but the entire structure of the book is meant to bring the reader to that very conclusion. Why doesn't Shlain tell us which brain wave is dominant when we eat, or dream, or have sex? Studies of these activities have been conducted since the EEG was invented, but too many relevant facts threaten his thesis, so a fuller context must be ignored. This isn't just sloppy scholarship--this is manipulation.