This book is excellent. I bought it at the same time as the Pattern Recognition (Sergios Theodoridis and Koutroumbas) hoping it would clarify by example.
After trying to battle through Pattern Recognition I decided instead to start into this book instead. I've nearly finished reading it cover to cover along with doing some of the Matlab exercises. I've found it really well structured, and gives a very 'visual' approach to understanding the techniques.
Contrary to what one might expect, I'd recommend learning from this book and only resorting to it's big brother once you need more info. This book is much more digestible!
You'll probably want to have at least about first year uni level maths to appreciate all of the concepts fully.