Utter dross. One of the frustrating things about books like this that are blatantly lying or deliberately misinterpreting things is that it calls into question even the more reasonable claims that they make. Aside from the wild speculation about possible Martian civilisation based on 'it kind of looks like there's a face in one of the early probe pictures' and a bunch of dubious (and dubiously meaningful) math, there's a strong focus on the possible danger of near-Earth space objects (comets and asteroids etc). What they say about that could well be accurate enough, but because it's used in aid of obvious bunk and alongside things that are I can tell are wrong there's just no reason to think any of that is accurately presented either. It compiles huge amounts of information, but it's all completely meaningless.
It also has a weirdly religious moralising conclusion about how maybe the earth is due for destruction by (totally not a god) some supreme intelligence that is upset by all the evil in the world.