I would consider the book a crucial read for anyone who is designing or building products that other people will use to (from the POV of the user) do something meaningful/useful.
But it's also primarily a book about how to make getting significantly better at something -- knowledge and especially skills -- more effective and efficient. That's where most of the science behind the book is applied.
The basic premise is:
If you want a successful product, the only sustainable answer is that it must actually *work* for the users in a way that makes them significantly better *at whatever it is they were hoping to do with it*. The rest of the book is about how to actually make that happen.
Ahh -- the 'real meetings steal your soul' that was in my book trailer video was just an over-the-top reference to struggles of normal daily life. I've seen so many products (and especially documentation and support of those products) that appear to have been designed and created for people who have literally NOTHING else to worry about in their life at the moment in which they are using the product. We have to put our users in the context of not just what they're doing at the time they sit down to interact with the product but the rest of their day. And week. And life. Because by the time they start interacting with our product, they may be so low on cognitive fuel. It's not that they are stupid, or lazy, or not willing to RTFM, etc. -- it's that they have a brain that has been struggling with a million other things unrelated to our product.
The book is about how to help them move forward *within the context of life-is-not-perfect*.