Earthquakes are catastrophic events that cause huge economic losses due to the vulnerability of the existing building stock. However, collapses of vulnerable buildings can be avoided if preventative measures, such as enhancement of their earthquake resistance, are implemented on time. This book will allow the reader to become acquainted with a number of unique, modern and cost-effective seismic isolation strategies, which can be easily, and in very short periods of time, and without interruption of the use of the buildings, implemented with high efficiency in existing buildings, making them earthquake proof. An important aspect here is that the book's seismic isolation strategies are demonstrated on real examples of existing buildings with different structural systems, such as reinforced concrete frame buildings with shear walls and stone buildings with load-bearing walls. The cost-effectiveness of the suggested strategies is further proved by comparative analyses carried out for buildings both with and without seismic isolation systems.