The quest for sustainability will increasingly concentrate development in cities, generating a greater fusion of old and new styles of architecture, especially as policy incentives are implemented that encourage major additions to existing buildings. Charles F. Bloszies, AIA, author of a forthcoming book from Princeton Architectural Press exploring this trend, will join preservation architect Charles Chase of Architectural Resources Group, Anne-Catrin Schultz, author of Carlo Scarpa--Layers (Menges, 2007) and real estate broker Dan Cressman of Grubb & Ellis in a discussion of the complex issues involved. Moderated by Tim Culvahouse, editor of arcCA. Co-sponsored by AIA San Francisco.