Smolin is taking on all of modern physics in this book. His core assertion is that the laws of physics are not timeless, and that these laws both incorporate, and also evolve over, time.

This is a much more difficult read then Smolin's previous book "The Trouble with Physics", and some of the arguments seem circular. However, stick with it, as he makes several thought-provoking points towards the end of the book, when his arguments start to come together.