The material in this book is difficult for me, even though I have a PhD in Engineering and an MS in Computational Mathematics.<br><br>On the contrary, I believe that Kreyszig's Advanced Engineering Mathematics is accessible to anyone with a "rusty" calculus.<br><br>As a result, if anyone finds Arfken's book too difficult to read, I recommend reading Riley's book (Riley-Hobson-Bence) first.<br><br>Starting with Kreyszig's book is also a good idea. It includes topics like Fourier Analysis and PDE, Complex Analysis, Linear Algebra and Vector Calculus, but excludes Tensors, Hilbert Spaces, and Calculus of Variations.