Full disclosure: currently working on research under one of the author's PhD advisees, now a professor himself. (The research is tangentially related to the topics of this book and I used it to get some background in the matter.)<br><br>Excellent book, very clearly written. As a rising third-year physics major I found it very digestible but still challenging (only used the first 8 chapters so far). I had to read it fairly quick as it was background for research, but looking forward to doing another more careful read and continuing on into the sections on chaos and fractals. It's a small thing, but I particularly liked the chart in the first chapter where he groups various problems/topics in physics and other sciences by number of variables and linearity vs. nonlinearity, then qualitatively explains the chart and the relative "solved-ness" of each area. It's nothing mind-blowing, but it's just a very tidy chart that would have been nice to see earlier in my physics/math career.<br><br>One of the reviews on the back says something about the book being well written to the point of being likely to convince people to change their major or really begin to appreciate the beauty of math. As a student I can confirm this and am considering how to work applied math and nonlinear dynamics into future graduate studies.<br><br>This isn't the best book for people without a strong calculus background or those who don't want to read their share of equations and graphs, but if you are a non-mathy person and happen to come across it, the first chapter or two, plus the more qualitative pieces scattered throughout, may still be enlightening.