We humans are difficult animals. We are the source of environmental degradation, the culprits of resource decline. We are reluctant to trust and easily angered. However, we are also the source of inspiration, compassion, and creative solutions. What brings out the reasonable side of our capacity? The Reasonable Person Model (RPM) offers a simple framework for considering essential ingredients in how people, at their best, deal with one another and the resources on which we all rely. RPM is a hopeful and engaging framework that helps us understand and address a wide diversity of issues. The 20 chapters of Fostering Reasonableness provide the conceptual foundations of the framework and applications examining contexts as diverse as a region, organization, the classroom, finding common ground in resource planning, education in the prison environment, greening in the inner city. Our collective hope in putting the book together is to encourage a way of seeing, a way of understanding and examining circumstances that might lead to more wholesome, adaptive, and effective means of addressing the big and little issues that depend on humanity’s reasonableness.