For a mathematician like me, who took Further Maths A-level 20 years ago, this is an accessible introduction to a complex subject and I would highly recommend the book on that basis.
There were a few bits of calculus that caused me a bit of trouble, but nothing that could not be sorted out following a quick search of the web. For me, this book was a perfect follow on from the UK Association of Corporate Treasurers' Certificate in Financial Mathematics. The book also contains numerous exercises and MATLAB references if you want to delve a little deeper.