3Urban Grids: Handbook for Regular City Design is the result of an eight-year research project undertaken at the Harvard University Graduate School of Design. The book emphasizes the value of the regular city as an open form for city design, and specifically insists that the grid has the unique capacity to absorb and channel urban transformation flexibly and productively. Research into existing cities and projects is revealing new emerging conditions for the urban grid, presented here as possible paradigms for the city of the future. The work is organized into six parts: 1. The Atlas of Grid Cities; 2. Grid Projects across History; 3. The Twentieth-Century Dilemma; 4. The Emergence of New Urban Grids; 5. Projective Design Tools; 6. The Good Grid City as Open Form.