Dynamic environmental processes are complex; the easiest and most effective way to understanding them lies through the disciplines of dynamic modelling and computer simulation. The prerequisite modelling fundamentals are presented in the first chapter in a manner comprehensible to students as well as to practising scientists and engineers. The second chapter describes the many environmental processes that lend themselves to modelling, for example pollution and wastewater treatment. The third part of the book provides 65 simulation examples both on the page and on an accompanying diskette in the simulation language ISIM - the first time that this has been done with a teaching book in this field - ready-to-run on any DOS personal computer. Crucially, the simulation runs can be interrupted to allow rapid interactive parameter changes and easy plotting of results; this enables the reader to get a feel for the model and system behaviour.