This lecture explores the anatomy of an intelligent building as a layered, interconnected system. It introduces the six key layers—physical, sensing, communication, control, intelligence, and human interface—along with feedback loops, agents, actuators, and control strategies. The lecture also examines key building protocols and standards such as BACnet, KNX, Modbus, MQTT, BRICK, and Project Haystack, highlighting their importance for interoperability and intelligent building performance.