Einstein said “I want to know how God created this world. I am not interested in this or that phenomenon. I want to know His thoughts; the rest are details.” This is the difference between fundamental physics and what we might, for lack of a better term, call normal physics: Why is the world the way it is at a fundamental level versus what is the explanation or characterization of some given phenomena? Fearful Symmetry by Tony Zee is about the former.
The quest is follows the trail blazed by symmetries in physical laws, where a symmetry has obvious analogues to everyday experience: You do something to a thing and it remains the same. Rotate a uniform ball by any angle and it looks the same. At issue are whether the laws of physics themselves obey certain symmetries. If you rotate your point of view, will the results of the experiment come out the same way? Turns out, by following such a schema you can go very far indeed. In this way the modern theoretical physicist is less like the gentleman scholars of the 1800s (one pictures Michael Faraday putting in many hours hunched over pools of mercury and wires) and more like an architect or a sculptor, keenly aware of symmetry and aesthetic beauty and utilizing them to guide their work.
I’d like to have given Fearful Symmetry to my younger self, back in junior high when I was starting to read popular books on theoretical physics. More so than some of those books, it attempts to convey some of the more concrete tools of the physicist, like action or group theory, rather than hand-wavingly refer to “beautiful mathematics that you are unfortunately too much of a newb to comprehend.” Of course, it’s still a popular science book and so the math is necessarily light.
For this reason I’m going to start moving up the value chain and reading/reviewing more technical books (the next on the hit list is a straight-up textbook). However, I recommend Fearful Symmetry to anyone who wants to get a flavour of the way that fundamental physics changed over the course of the 20th century. You started with the stereotypical view of a physics professor with chalk on their hands and machine oil on their pants and moved to almost a religious caste of monastic monks, worshiping at the altar of symmetry, beauty, and Yang-Mills (though experimental validation is still a must). The questions that arise are the most profound of all: Why is there stuff in the Universe? Why is the Universe the way it is and not some other way? Why is gravity so feeble? Where’d all the antimatter go? I wonder in a century what questions will be considered still profound and which will be run-of-the-mill.