The book reconstructs the story of a small but interesting project by the architect Pier Luigi Spadolini and, in unpublished documents, proposes a new reading by the technology that reveals some surprising connections. The research design is conducted and driven by a path that crosses the history of a major industrial company in the Tuscany territory now multinational. In this context this precursor project brings to a strong focus on the environment and that after 25 years could be defined as an early solar energy retrofit project.