This book documents the transformation of the Ancien Manège in Geneva, a horse riding hall that was built in the 19th century and converted into a garage in the 1950s. Around 200 pages long, it brings together texts, photographs, plans, construction details and specifications in both French and English. The publication traces the history of the Manège, the participatory process that led to its transformation into a civic building, the architectural project, the execution of the works and the building's current use. With graphic design by Studio Mut, it includes a series of conversations curated by Isabel Concheiro and photographic essays by David Grandorge, Andrés Fraga, Didier Jordan and Luis Díaz y Díaz. The book highlights contemporary issues relating to heritage transformation, sustainable development and shared governance. Intended for both professionals and the general public, it offers an in-depth perspective on an exemplary reuse project within a complex urban and historical context.