This lecture focuses on the essential principles of structural design, emphasizing the various factors that architects must consider when designing buildings. It begins with a summary of the fundamental guarantees a structure must provide, such as safety, comfort, cost-effectiveness, and environmental quality. The instructor discusses the influence of loads, support points, topology, materials, geometry, proportions, and construction methods on structural integrity. Through examples, the lecture illustrates how different choices impact the overall performance and efficiency of structures. The discussion includes historical references, such as the Cathedral of Amiens and the architectural innovations of Eduardo Torroja, highlighting the evolution of materials and design approaches. The lecture concludes with a reflection on the importance of collaboration between architects and engineers to achieve optimal structural solutions that meet both aesthetic and functional requirements.