It was largely overblown due to it getting banned. It was also published in the height of the Vietnam War, when the big evil communists were coming to brainwash your children into eating each other. It has a lot of blatantly incorrect info, which could be outright “blow up in your face” dangerous to anyone attempting the things in it. It’s not all wrong, but certain recipes have incorrect info that could easily lead to accidents.

Also fair warning, the UK will give people hard prison time simply for owning it. So maybe keep that shit onion-encrypted if you’re in the UK.

I linked to the Wikipedia article, not the handbook inself. And more for the (obsolete) phreaking content than the (highly dangerous) explosive content.