Some of the examples are going to be corny for a young kid, but none of the core concepts are too challenging. Some fashion of the knowledge has probably already been communicated to children, it is just a codification of social interaction that not everyone has passively absorbed.
It's pretty easy to read (but disclaimer : I read the french translation) but it's still nothing more than a list of useful advices on the topic. So the prerequisite is that you have to be interested by the idea of the book in the first place. But if you are, it's nothing more than a big blog post (a good one).
No it's ok, it reads like every american self-help book translated in french. The writing style is pretty bland but it's easy to read and the only difference with most of self help books nowadays is that the advices are actually good.
The good thing about the absence of style is that the book doesn't feel dated and could have been wrote yesterday.
To be honest, the examples stuck with me. They illustrated tons of different social interaction examples that I have seldom, if never, encountered in my life, but have plenty to learn from.