This book is concerned with a leading-edge topic of great interest and importance, exemplifying the relationship between experimental research, material modeling, structural analysis and design. It focuses on the effect of structure size on structural strength and failure behaviour. Bazant's theory has recently found wide application to all quasibrittle materials, including rocks, ice, modern fiber composites and tough ceramics The topic of energetic scaling, considered controversial until recently, is finally getting the attention it deserves, mainly as a result of Bazant's pioneering work. In this new edition an extra section and new appendices covering the most recent developments in the subject are included.