This study provides a comprehensive archaeological and philological investigation into multi-storey residential building blocks and insulae in Imperial Rome. Grounded in a rigorous analysis of structural remains, epigraphical evidence, and literary sources, the research re-examines the typology, terminology, and living conditions associated with high-rise domestic architecture. A central focus is given to the Insula dell'Aracoeli at the foot of the Capitoline Hill, offering a revised spatial and structural reconstruction within its urban micro-topography. The study critically analyzes internal layout, upper-floor apartments (cenacula), staircases, access systems, and structural alterations over time. Furthermore, it re-evaluates the historical and legal semantic range of the term insula, contrasting modern scholarly assumptions with ancient perceptions. By contextualizing these structures alongside comparative evidence from Ostia and Pompeii, the monograph elucidates socio-economic dynamics, rental practices, urban hazards, and the architectural reality of life ad summas tegulas.