The information, opinions, and stances contained in the book are presented in such a way that there is (not much) room for doubt about their credibility. The sources that Chomsky uses, as I understand it, are available but in the American media are either forgotten or presented as irrelevant.
At the end of the book, as expected, Chomsky poses the question of what the "average" citizen can do to influence the political circumstances in the country where he lives, and, among other things, says the following, and thus concludes:
"If elections are mostly something in which one part of the population participates by pressing a button every few years, they mean nothing. But if citizens organize in support of a certain stance and exert pressure on their representatives regarding that stance, then elections mean something. [...] We don't know if sincere and dedicated efforts are enough to solve such problems, or even just alleviate them. However, we can be quite sure that the absence of such efforts guarantees a catastrophe."