This was enjoyable. The premise reminds me of Interstellar, especially the time aspect. I also liked his take on social unrest not being able to be manufactured.
It's astonishing to note that this book was written 40+ years ago, yet the idea was still very advanced in the current era. Yes, it's difficult to imagine the use of common objects, say, a torch, just 500 years ago! The first-generation Iphone was only released as late as 2007! So what would happen in a decade after?