Here's a book that is good but could be better.
It has the general aim of explaining the current state of fundamental physics, first in terms of the physics itself and second in terms of how it is practised (with particular reference to the USA).
Smolin starts with five big problems extant in fundamental physics. Here, right at the beginning, comes the first weakness of the book: two of these fundamental problems may not be problems at all. One is the so called "observer problem" of quantum mechanics. Many highly competent physicists don't think there is any "observer problem" at all - this is barely acknowledged anywhere in the book. The second is the 20 arbitrary constants of the Standard Model - many physicists find these 20 constants annoying and would like some deeper explaination of them. There is, however, no reason to think any such explanation exists, except insofar as there is reason to think (because of the other three big problems) that there is a more fundamental physical theory than the standard model. He also seems to have missed a couple of questions I would ask (though maybe they have actually been explained and I don't know about the answers).
The next weakness is in Smolin's explanations. Whilst talking about the Standard Model and General Relativity Smolin is somewhat unclear a number of times. In the former case a more detailed description of precisely what is included in his definition of the Standard Model is required even though this is a fairly hefty deviation on his road to explaining String Theory. In the latter, I was confused by a statement about the Principle of Equivalence that I'm sure actually just means that General Relativity is a local and Classical theory - not controversial at all - but seemed to say that one could tell gravity from any other acceleration simply by waiting long enough...
Smolin's (and almost everybody else's) explaination of the "Gauge Principle" relies on its symmetry properties and is not all that clear. This is like explaining conservation of charge by its symmetry properties - missing the fundamental point. People make this mistake because the principle was recognised as necessary from the the symmetry requirements of theories that would explain the observed fundamental particles. For the record the Gauge Principle is that phase is locally conserved.
The above leads me to wonder how many mis-apprehensions I've been left with when Smolin leads me into unfamiliar territory....
The reader is then given a long section explaining why String Theory is neither a theory nor physics. The length is unavoidable if a proper treatment of the topic is to be made. This confirmed my own opinion that it simply isn't worth my time to try to get a more mathematically sound grasp of the concepts.
Next comes a set of different (i.e. non-stringy) ideas for dealing with any of the five problems mentioned at the start. This was by far my favourite part of the book because it presented ideas that were entirely new to me.
After this comes a section where-in Smolin muses on the nature of science and the gap between the ideal and the reality. This is largely a disaster. The two chapters on the definition of science contradict much of what is obviously Smolin's true belief on the matter, as gleaned from his complaints about String Theory earlier on. They also contain a huge heap of ill-conceived pseudo-scientific mumbo jumbo that is embarrassing to read from such an intelligent man.
Finally Smolin gives his view of how physics is being smothered by the academic system. This applies in detail only to the USA. He regains my respect by offering actual concrete policies for changing the system that could be implemented; so many people in so many walks of life merely complain and can't offer a suggestion for a solution. My view is that the most useful suggestion he makes is the hardest to implement; the abolishment of tenure.
Well, that all seems pretty harsh! Smolin can't complain about that given what he hands out to others in this book, however. It is definitely worth reading if you want to get a grasp of what String Theory can do (nothing) and why. I (as ever) have no idea how some-one without a strong physics background would cope with the book.