Earthquake engineering (EE) is an integration of multidisciplinary knowledge in several areas of basic sciences and science-based engineering with the ultimate goal of reducing the seismic risks to socioeconomically acceptable levels. In the U.S., the first comprehensive book covering various aspects of EE was published in 1970, the result of a short course on the subject given in September 1965 at the University of California, Berkeley. There have been recent advances and new developments in EE on a wide range of topics, from geosciences and geotechnical engineering to modern performance-based EE. These advances are usually published in scientific and technical journals and reports or presented at national and international conferences. This book has been written with the intention of presenting advances in scientific knowledge on various EE topics in a single volume. Although it has not been written in a traditional textbook format, this book can serve as a guide for instructors, graduate students and practicing engineers. We hope it will contribute to the teaching of modern EE and its applications to practice, as well as to the formulation and evolution of research programs. The 19 chapters in this book can be grouped into the following main parts: • Historical development of EE and its modern goal (one chapter) • Geoscience principles needed to define seismic hazards (two chapters) • Engineering characterizations of ground motion, as well as geotechnical hazards (two chapters) • Deterministic and probabilistic methods of analysis (two chapters) • Performance-based EE, its applications and future direction (two chapters) • Innovative strategies and techniques (three chapters) • Seismic behavior and earthquake-resistant design of building structures using different structural materials (six chapters) • Seismic analysis and design of nonstructural elements (one chapter) The multidisciplinary nature of EE makes it very difficult to cover the details of all the scientific and engineering aspects involved in modern EE in a single volume. Due to space constraints and also to the existence of other well-written books and handbooks, we have not covered some important EE topics in this book. These include an elaborate discussion of linear structural dynamics; architectural considerations; seismic behavior and design of lifelines and industrial facilities; risk management; and social, economical and political planning. The breadth of EE makes it impossible for one person to authoritatively write about all relevant topics. Therefore, to create a comprehensive book on EE, the contributions of many experts are essential. This book is the result of an enormous amount of time and energy spent by a panel of distinguished contributors whose collective experience exceeds 500 years of teaching, research and practice. The efforts and cooperation of the contributors are greatly appreciated.