I am currently a staff member for the MITx/edX 8.04x-8.06x Quantum Mechanics MOOC's, and I have found that students there although very motivated, often have a very limited and narrow  education in physics: mechanics -&gt; electromagnetism -&gt; waves -&gt; quantum mechanics.  I often recommend that students in these courses read the Feynman Lectures on Physics, and Longair's book on Theoretical Concepts in Physics, as a way to broaden their knowledge. Now I would also recommend these students read Fly By Night Physics, another Tony Zee masterpiece I am happy to have in my physics library.<br><br>I consider the author Tony Zee one of the best writers on theoretical physics both on a popular and textbook level.  He has written three previous textbooks, Quantum Field Theory in a Nutshell, Einstein Gravity in a Nutshell, and  Group Theory in a Nutshell for Physicists, as well as numerous popular books on physics and other esoteric subjects.  The Nutshell books (a Princeton University Press series of books on theoretical physics at the advanced undergraduate/graduate level) usually have a length of 300-500 pages.  The joke with the nutshell title in Zee's books is that his are 600-800 pages, and would hardly fit in a nutshell.  Still they are a superb set of books, the QFT book the premium concept book on quantum field theory, The Einstein Gravity text probably the best introduction for undergraduates, yet still containing (as Zee usually does in all his textbooks) advanced material at the end of book such as twistors, and Group theory probably the most accessible book on learning this important topic for future particle physicists, and also containing advanced material such as Dynkin diagrams and Grand Unification.<br><br>Now Zee has written a wonderful new book that truly is of nutshell size (400 pages), titled: Fly By Night Physics (How Physicists Use the Backs of Envelopes).  I consider the book which is written and targeted for advanced undergraduates in physics, as an in-between book for physics majors, less of a textbook, and much more than a popular book, and a joy to read as usual for a Zee book.  As Zee notes in his preface, the book does not cover the type of problems known as a "Fermi Problem" such as estimating how many piano tuners there are in Chicago.  Rather the heart of Zee's book is to show and teach that almost any advanced physics equation can be derived and understood using dimensional analysis, symmetry, scaling, and a few other Fly by Night assumptions, such as "The dull function hypothesis".<br><br>Almost all freshman physics students learn how to derive the period for a pendulum (l/g)^(1/2) using dimensional analysis.  Some may have seen it used (as Zee does also) to derive the energy released in the first atomic bomb blast from just a few photographs.  And students of quantum mechanics often see this reasoning in estimating the Bohr radius.  But then most students of physics (myself included) file away this valuable tool, and rarely use it again.  This is the purpose of Zee's book to show that these tools can be used in all areas of advanced theoretical physics over and over again.<br><br>Thus in the first few pages he not only shows the pendulum example, but quickly follows it with a few sentence derivation of an equation for the perihelion precession of Mercury under general relativity, as well as the deflection of light.  And the book continues with examples from all areas of physics, including diffusion, the 1/r falloff of electromagnetic radiation fields, the Larmor formula for power radiated by an accelerating charge, Thomson scattering cross section, Compton scattering, tunneling in nuclear physics, scaling the hydrogen atom (Zee has a nice section on which element is the smallest atom - you may be surprised by the answer), blackbody radiation/Planck distribution, Fermi-Dirac and Bose-Einstein distributions, Planck units and quantum gravity, black holes and entropy, Van der Walls law and phase transitions, Bose-Einstein condensation, symmetries of rotations, parity, time reversal, fluid dynamics and Galilean invariance.<br><br>There is a whole part on astrophysics and cosmology including White dwarfs and the Chandrasekhar limit, neutron stars and of course black holes, and a wonderful chapter on the power radiated in gravitational waves. The books penultimate part is on water waves including a chapter on drag, viscosity, and Reynolds number.  The final part of the book is the usual Zee end of book advanced topic, in this case particle physics a brief tour from Feynman diagrams to weak interactions and charm.  Additionally the book contains three so-called math medleys, where the author shows how to derive the the general formula for the area of a triangle, using just symmetry, scaling, and various other tricks, as well as treating Feynman integrals, and random matrix theory.<br><br>So how is it possible to cover so much material in so short a book?  Because Zee is a master at getting to the essence of the physics,  There are no involved lengthy calculations in the book, so the 2's, 4 pi's and other constants are ignored.  Just the important and essential physics of the key equations are derived and explored.  This makes the book an easy read, without the requirement of pen and paper nearby.  And in case you are worried that your undergraduate physics knowledge has expired, or you just need a refresher, the book has a total of 12 short appendices on topics such as the Dirac Delta function, Einstein Gravity, Euler and Naiver Stokes equations, Green functions, and Maxwell's equations.<br><br>So who would I recommend this book for?  Certainly advanced undergraduate students in physics and graduate students as well.  But it should also appeal to those Zee refers to as the autodidacts, or the self taught and self learners who will find that the book is a very useful introduction to topics that they may not yet have encountered. This is not a popular physics book, so for those with little physics background or knowledge, I don't recommend this book, but I would recommend looking at several other popular books that Zee has written.  Finally if you are a mathematician and Bourbaki rigor is your cup of tea, this book might give you some indigestion, but then again most theoretical physics books would do that as well.