Omgiven av idioter

The most useful takeaway from the book is that there are different types of people. You need to adapt to that and treat people differently. The framework that the book uses to classify people is perhaps best thought of as an example of how you could group different people. It is in no way the only or best way to classify people. The book has zero references to scientific studies and instead focuses on the personal experiences of one individual. That doesn't mean that the book and the ideas aren't useful, but they are definitely not undisputed facts.

All in all, if you value examples and an easy and useful mental framework then this is for you. If you want facts, look elsewhere.