A Line in the Andes -- a one year investigation developed at the Harvard Graduate school of design -- examines the transformative role of the first underground metro line currently being implemented in the city of Quito (Ecuador). Through archival material, original drawings, and text, this publication frames the metro project within the city's historic and current urban form, visualizing the urban potential of this contemporary valley-city. In doing so, the material documented in this book sets the stage for well-informed design deliberations regarding an urban future Quito deserves. The book also includes a collection of essays by Rahul Mehotra, Quito Mayor Augusto Barrera, Edgar Jacome, Pablo Perez Ramos, Martin Cobas, Graciela Silvestri, and Ana Maria Duran Calisto. The writings expand on a series of themes related to Quito and frame the city within a broader geographic and disciplinary context.