This book is a broad swath of cold, mechanical mathematics. The first half is a focus on the many ways of solving ODEs and PDEs using a huge number of tools like Linear Algebra, Fourier analysis, Laplace transforms, and vector calculus. The second half is some numeric analysis, graph theory/optimization, and probability/statistics. All valuable stuff to know as an engineer.
This text has a number of issues, the biggest being the complete lack of applications. Every chapter is straight theorems and proofs, a couple of examples, and then problems to work at the end. The examples given are usually poor or leave you in the dust on many of the practice problems, and the chapter summaries are often too sparse to be useful refreshers. Unfortunately, this uninspiring work seems to be the gold standard in many graduate level mathematics classes.