Modern Electrodynamics, AndrewZangwill, Cambridge U. Press, 2013. $85.00 (977 pp.). ISBN 978-0-521-89697-9
In Modern Electrodynamics, Andrew Zangwill and Cambridge University Press have created a hefty, readable modern textbook on classical electrodynamics aimed at advanced students of the subject. Author and publisher set an ambitious goal, given the formidable competition from existing, well-deserved classics on the subject; the result is a worthy addition to the literature.
Modern Electrodynamics is large: more than 900 pages of text, examples, and hundreds of problems, organized into 24 chapters. Given the imposing size, I was reassured to find at the top of the very first page a quotation attributed to physicist Kenneth Johnson: “A textbook, as opposed to a treatise, should include everything a student must know, not everything the author does know.” Anyone with the good taste to select that epigram, from such a great teacher, is well worth reading.
Among the other interesting quotations that spice up Modern Electrodynamics is Richard Feynman’s answer to why one should write a new textbook on such a well-covered subject: “Why repeat all this? Because there are new generations born every day. Because there are great ideas developed in the history of man, and these ideas do not last unless they are passed purposely and clearly from generation to generation.”
The first chapter summarizes mathematical tools. That unconventional start makes sense. Most readers will be familiar with the mathematical preliminaries; it is helpful to establish standard nomenclature early to keep the focus on physics later. And collecting the mathematical tools at one location enhances the book’s reference value. Mathematical topics crucial to electromagnetism—solving Laplace’s and Poisson’s equations—are each covered in their own chapter. Chapter two, “The Maxwell Equations,” is a delightful whirlwind tour. It touches on history, on Zangwill’s choice of Lorentz averaging to relate macroscopic sources and fields to rapidly varying microscopic values, and on the role of classical electrodynamics in our real world of atoms interacting through electric and magnetic forces and subject to the rules of quantum mechanics.
The meat of the book, chapters 3 to 23, proceeds in a conventional order: electrostatics—from vacuum to conductors to dielectric materials; followed by steady currents, magnetostatics, and magnetic matter; then building up to dynamic fields and electromagnetic waves in various media; and then on to radiation, scattering, diffraction, special relativity, and fields from moving charges.
Modern Electrodynamics makes good use of certain modern elements of page layout and manages to avoid the more annoying ones. Most chapters have several sidebar “Applications” that relate the material being developed in the chapter to classic electricity and magnetism problems, research-level examples, or technical devices. In a helpful touch, those applications have their own table of contents. The book also contains sample problems presented in screen-tinted text boxes. Generally, the examples are well stated, as are the actual homework problems, and their solutions are developed clearly and concisely. Each chapter concludes with a detailed and informative section on sources, references, and additional reading.
I enjoyed examining this handsome book, finding favorite topics described in fresh ways and learning about other topics. Zangwill’s writing and mathematical demonstrations are crisp and to the point, and they generally complement each other well. Sprinkled throughout are various gems of historical and scientific interest, such as the stories of the operation of a vacuum-tube triode and the “miller of Nottingham,” George Green of Green function fame (see the article on George Green in Physics Today, December 2003, page 41). The high points for me are chapters 5, 6, and 13, on materials, and chapter 14, “Dynamic and Quasistatic Fields,” in which Zangwill addresses the pesky issues of dissipation, skin effect, and eddy currents before moving into full-blown electrodynamics in subsequent chapters.
The book’s weakest part is its treatment of special relativity. Uncharacteristically, Modern Electrodynamics largely misses the grandeur of Lorentz invariance, embedded in electrodynamics from its inception but hidden from full view until Albert Einstein recognized its implications and replaced Newton’s concepts of space and time with spacetime. Zangwill’s choice of Minkowski’s imaginary component in four-vectors is strange; given the straightforward mathematics of special relativity, that choice adds unnecessary complexity and heightens the potential for confusion. Also, numerical methods are not addressed in this book.
I sometimes advise advanced undergraduates to begin building their own physics libraries with classic advanced textbooks, even before the books are assigned in class. Such texts can broaden perspectives on core subjects and would be readily accessible as the student advances in his or her studies and work. Where shall I put Modern Electrodynamics on such a reading list? It has a lot to offer, so I think it should be somewhere pretty high up, but after John David Jackson’s Classical Electrodynamics (3rd edition, Wiley, 1998), David Morin’s update of Edward Purcell’s Electricity and Magnetism (3rd edition, Cambridge University Press, 2013; reviewed in Physics Today, August 2013, page 48), and the timeless classic, Lev Landau and Evgeny Lifshitz’s Classical Theory of Fields (Addison-Wesley Press, 1951).
Roy Schwitters is the S. W. Richardson Professor of Physics at the University of Texas at Austin, where he studies many topics and teaches electrodynamics and other subjects in physics.
