The third volume of the Palinsesti Romani series continues the work and interdisciplinary study and research method of the second volume, dedicated to the Roman houses below the Basilica of Saints John and Paul (CAELIUS II, 1). Therefore the present works conveys the research results of the pars superior of the same site. The text offers a broad account of the studies on the basilica, and its complex building and figurative phases. The text is enhanced by an interpretative hypothesis on the plant, elevation and structure of the nearby temple of Claudio. The specific studies by archaeologists, architects, art historians and restorers have been enriched by antiquarian and archive sources and illustrated by a widespread graphic and photographic documentation, which also illustrates the restoration works carried out by the Soprintendenze di Stato between the end of the 20th and the beginning of the 21st century.