It’s a highly opinionated book but it is full of good advice that in my opinion goes too far. Using a metaphor here, I think he wanted to get people to the moon but knew that he needed to give guidance to get to mars because people would look at whatever he wrote and think it’s too much.

The book has several chapters discussing the SOLID design principles and showing how to apply them. You’ll be a better programmer for reading it. “Uncle Bob” the person can be a bit problematic so I don’t particularly like telling people to give him money. Try getting the book from the library or a second hand store. There are also videos out there of him speaking at conferences that may give a good taste of the material. He has a blog too.