# BOOK REVIEW: The Theoretical Minimum: What You Need to Know to Start Doing Physics by Leonard Susskind and George Hrabovsky

## Review by Tom Siegfried

Most popular books on physics attempt to explain ideas without equations (the popular dogma says that each equation cuts sales in half). But when the book’s advertised purpose is to provide the (minimum) knowledge needed to actually do physics, equations are a must. And this book is full of them.

Susskind and Hrabovsky introduce dynamical systems and vectors, then lay out the basics of calculus, building the basic mathematical toolkit that physicists rely on. Then come energy, symmetries and conservation laws, along with increasingly elaborate mathematical notions to deal with them. Once you get through Lagrangians, Hamiltonians and Poisson brackets, you’ll just have to grasp gauge symmetries and vector potentials. Then you can dazzle your friends by analyzing the decay channels for the Higgs boson.

Or maybe not. This is a spectacular effort to make the real stuff of theoretical physics accessible to amateurs. But it’s hard to see how anyone not already comfortable with calculus will be able to stick with it. Even those with math skills won’t be ready to travel with pioneers at the theoretical frontiers. This “theoretical minimum” is for classical physics — there’s no relativity, no quantum physics, no cosmology. That will all presumably have to wait for the next book (which will, in fact, be worth waiting for).

But even if this first effort fails to make every reader capable of doing what physicists do, it certainly will improve most readers’ ability to comprehend what physicists say. And that may be even more valuable: No doubt the world needs a better understanding of physics more than it needs more amateur physicists.

*Basic Books, 2013, 238 p., $26.99*