A mathematical model of a physical system provides the engineer with the insight and intuitive understanding required to make efficient system design changes or other modifications. In this context, a simple formula is often worth a thousand numerical simulations, and connections between different control parameters can be immediately revealed that might otherwise take hours or weeks to deduce from a computational analysis. This book supplies the undergraduate engineer with the basic mathematical tools for developing and understanding such models, and is also suitable as a review for engineering graduate students. A firm grasp of the topics covered will also enable the working engineer (educated to bachelor's degree level) to understand, write and otherwise make sensible use of technical reports and papers.