This book addresses one of the most pressing issues of our time: How can we design for, with, and in service of the complex world we live in? How can we be useful as designers in a rapidly changing world due to technological, political, and social processes, as well as climate change and nature destruction? Designers have some beneficial skills for planning with complex systems in mind, yet some old habits need to be overcome. Design's traditional purpose and role has been to solve problems, find order, organize, and simplify. Yet, the concept of designing complexity goes against these established beliefs because complexity cannot be designed away. So, instead, we present ways to live with, influence, and benefit from complex systems. There is no one "right" way presented in this book. Instead, many experiences, approaches, and perspectives are collected and presented. The process this book offers is a methodology called Systems Oriented Design (SOD). SOD is a design methodology and practice primarily geared toward understanding and working with complex systems. Several systems theories influence it, yet it remains true to its origin, the core of designing. SOD is a living and adaptable methodology. Though it is based on design thinking and design methodology, it is easily adapted and applied by anybody working with complex change processes.