The Sarno Bath complex (Regio VIII, Insula 2, modern house nos. 17–21) occupies the southernmost part of the city of Pompeii and it is unique in terms of size, architectural structure and functional aspects. The analysis of all published studies and documentation, available in the archives of the Archaeological Park of Pompeii, was the starting point of the project and it allowed to retrace the history of excavation and research from 1887 to this day. The study of Mau's and Sogliano's publications have led to know the course of excavations, the finds brought to light, the first functional interpretations of the building, its architectural evolution and, overall, a major structural failure that involved the westernmost part of the building. Because of this collapse, most of the vaults and the walls of levels −3 and −4 were reconstructed and the decorative apparatus was relocated. In the past decades, the research has focused on refining the interpretation of the first scholars in terms of construction techniques, usually with the goal of dating in absolute terms the architectural development, of defining the decorative apparatus and the function of each level, the ownership and the usability of the building, themes still unsolved. Unfortunately, most recent studies did not give due attention to the reconstruction carried out at the end of nineteenth century. Some examinations notice the different building materials, but they do not doubt the originality of today's plan. Some others relegate this news to the margin.