I have long had an interest in the life sciences, but have had few opportunities to indulge that interest in my professional activities. It has only been through simulation that those opportunities have arisen. Some of my most enjoyable classes were those I taught to students in the life sciences, where I attempted to show them the value of simulation to their discipline. That there is such a value cannot be questioned. Whether you are interested in population ecology, phar macokinetics, the cardiovascular system, or cell interaction, simulation can play a vital role in explaining the underlying processes and in enhancing our understanding of these processes. This book comprises an excellent collection of contributions, and clearly demonstrates the value of simulation in the particular areas of physiology and bioengineering. My main frustration when teaching these classes to people with little or no computer background was the lack of suitable simulation software. This di rectly inspired my own attempts at producing software usable by the computer novice. It is especially nice that software is available that enables readers to experience the examples in this book for themselves. I would like to congratulate and thank the editors, Rogier P. van Wijk van Brievingh and Dietmar P. P. Moller, for all of their excellent efforts. They should be proud of their achievement. This is the sixth volume in the Advances in Simulation series, and other volumes are in preparation.