Covers applicable mathematics that should provide a text, at the third year level and beyond, appropriate for both students of engineering and the pure sciences. The book is a product of close collaboration between two mathematicians and an engineer and it is of note that the engineer has been helpful in pinpointing the problems engineering students usually encounter in books written by mathematicians. Instead of just listing techniques and a few examples, or providing a list of theorems along with their proofs, it explains why the techniques work. The emphasis is on helping the student develop an understanding of mathematics and its applications.