Recycled Theory is a multidisciplinary dictionary made of entries in form of texts, drawings and quotes, which explore the concept of “recycling” in design cultures and in the theories that nurture them. The words here collected identify materials, procedures, ambiguities, deviations, and potential nexus of recycling, recording terms that tell the different processes of production and sense of city and landscape after recent socio-economic upheavals and the widening of preservation as the prevalent scenario for the project. Recycled Theory comes out of the collaboration of eleven Italian universities engaged in the research “Re-cycle Italy: New Life Cycles for Architecture and Infrastructure of City and Landscape.” The author has devoted an essay to "archeology", in Italian and English, identifying the history of archeology as an essential part of a more general history of recycling and as the vanguard of architectural history. The concepts of "excavation", "layer" and "life cycle"; "track", "indication" and "waste"; "archive", "site" and "context" have been investigated to unearth the deep relations between "Archeology", "Architecture", "History" and "Project."