This atlas is a unique conceptual tool to describe and analyze cities as complex systems, using a new, hybrid approach to urban land cover classification. As an impetus to bring ecologists and urban designers together, it builds on over a decade of shared knowledge from the Baltimore Ecosystem Study to inspire ecologically motivated design practice. Rather than separating human-constructed environments from predominantly biological and geological ones, this book integrates built and ecological structures and shows how this integration can contribute to the scholarship of ecology and the practice of design. The atlas displays maps and tables depicting these hybrid land cover classes and the relationships between them; information on how the specific patch arrangements evolved over time; and speculations on how cover might change through design, disturbance, or succession. Interdisciplinary and strikingly illustrated, the atlas is a new way to study, measure, and view cities with a more effective interaction of scientific understanding and design practice.