The monograph is subdivided into two parts. The first part presents concepts of seismology such as intensity or magnitude, together with probabilistic concepts related to the vulnerability and the potential damage that can occur in reinforced concrete and masonry buildings. Procedures for the preliminary design of buildings are included together with conceptual design recommendations. A brief introduction to the expert systems is made, presenting the qualitative reasoning systems in more detail and giving examples for the preliminary design of structures. Finally, a summary is made of the equations that govern the dynamics of linear and non-linear structures and their solution, including numerical procedures for the modal uncoupling and the step-by-step integration of the equations of motion. In the second part of the monograph, the non-linear behavior of structures subject to earthquakes is studied. This allows to predict the response of inelastic structures without the need of performing a non-linear analysis. The relative influence of various parameters such as structural damping, global ductility and the coefficient of strength is presented in detail. Next, the seismic action necessary in the analysis of structures is defined by means of accelerograms and seismic response spectra, but the one performed in several design standards of the world is also discussed. Finally, procedures are developed for the seismic design of structural elements and systems such as reinforced concrete ductile frames, dual systems and eccentric frames. The monograph includes a brief synthesis of earthquake-resistant design codes.