This book tries to cover pretty much all the mathematical methods you'd need in college-level physics if you haven't had much experience with them before. The trouble is that that is a LOT of math, and trying to cover that in a book this size is just asking for trouble.
If you don't know any of this stuff, this book is going to kill you. It covers multivariable and vector calculus, differential equations, linear algebra, functions of a complex variable, etc. That is maybe 4-5 different math courses. The idea is that physicists don't really need the rigor of theoretical math, they just need to learn the "tools" so they can do the practical, applied stuff.
This book is good if you already have a general idea of these concepts and just want to get the important parts.