A fundamental building type that has profound operational considerations on the fireground that is commonly found in nearly all jurisdictions and response areas throughout the United States. This program goes beyond the cursory discussions of “main street” unreinforced masonry (URM) and reinforced masonry (RM) construction and occupancies, but expands and explores the complexities of this heritage and legacy construction system and their renovations, adaptive reuse, make-overs and fireground operations. An overview of construction systems, materials and methods, inherent building characteristics, predictability of building performance, operational considerations, strategies and tactics with a focus on operational excellence and firefighter safety. Key Building Anatomy features, design and current architectural and design systems will be explored on this often neglected building system.