The Basilica of S. Maria in Cosmedin at Rome, situated on the banks of the Tiber over the former site of the Forum Boarium in the early Middle Ages, is one of the best known and most important churches of the city on account of its complex stratification that begins, at least, with the Republican period, on account of its architectural and artistic qualities, and on account of the sense of the sacred that permeates it. This volume covers in brief the entire history of the basilica and its context and guides readers in their visit. Contributing to this are the detailed inserts provided by experts in various fields.