"Each chapter provides additional information in an orderly way, elaborating on both old and new ideas at the same time, but also leaving enough space for readers to develop their own interpretations ... [The book] presents an array of valuable new data, and advances new theoretical approaches to its interpretation ... The main message is therefore not what has been achieved here—which is, undoubtedly, already significant— but what else might be achieved in future."Francesco Menotti, University of Bradford, UK