This monograph deals with the problem of reliability analysis in the field of Earthquake Engineering. Chapter 1 is devoted to a summary of the most widely used reliability methods, with emphasis on Monte Carlo and solver surrogate techniques used in the subsequent chapters. Chapter 2 presents a discussion of the Monte Carlo from the viewpoint of Information Theory. Then, a discussion is made in Chapter 3 on the selection of random variables in Earthquake Engineering. Next, some practical methods for computing failure probabilities under seismic loads are reported in Chapter 4. Finally, a method for reliability-based design optimization under seismic loads is presented in Chapter 5.