This book is about an approach to scientific research that seeks to look at the system instead of the individual processes. In this book I share with the reader my perspective on the study of complex relationships. The methodological framework I use in this enterprise is structural equation modeling. For many readers, this will be new and unfamiliar. Some of the new ideas relate to statistical methodology and some relate to research philosophy. For others already familiar with the topic, they will find contained in this volume some new examples and even some new approaches they might find useful. In my own personal experience, the approaches and methods described in this book have been very valuable to me as a scientist. It is my assessment that they have allowed me to develop deeper insights into the relationships between ecological pattern and process. Most importantly, they have given me a framework for studying ecological systems that helps me to avoid getting lost in the detail, without requiring me to ignore the very real complexities. It is my opinion, after some years of careful consideration, that potentially they represent the means to a revolutionary change in scientific inquiry; one that allows us to ask questions of interacting systems that we have not been able to ask before. These methods provide many new opportunities for science, I believe, and it is my hope that others will see their value as well.