This book is very well researched and documents the path the Sandworm hackers traversed over a number of years. I found the insight into Russian use of hacking in their overall worldview to be really interesting. Greenberg does a great job connecting all the dots and laying out a very solid explanation of GRU's hacking operations (beyond just the headline grabbing ICS attacks).
I am beginning to understand why people that work in ICS security are also some of the most off-the-grid-prepper types out there. I think the US is undermining all of us to keep a "competitive advantage." In the end, like the leaked NSA tools, it will be used against us. I for one won't be able to see I didn't see it coming.