In contrast to tabula rasa urbanism, this book considers strategies for tabula plena-urban sites that are full of existing buildings of multiple time periods. Such dense sites prompt designers to work between the fields of architecture, historic preservation, and urban planning, developing methods for collaborative authorship and interlocking architectural forms. The book grew from a collaboration between the Oslo School of Architecture and Design and Columbia University's Graduate School of Architecture, Planning and Preservation on the planning of the government quarter in Oslo. Emerging from this process, the book asks larger questions about how we practice, teach, and theorise engagement with existing architecture on an urban scale. It contains a compilation of short essays addressing theoretical questions, a sampling of design projects offering different formal strategies for architectural design, and a series of discussions about pedagogical strategies.