ABSTRACT
To provide a panorama of the field as fair and wide as possible, we as editors have striven to impose as few changes of content as possible to the chapters. One may appreciate this freedom by comparing what authors have to say about the relationship between Granger causality and the frequency domain quantities of Chapters 2 and 4. Rather than using or imposing our opinion in this and other matters, we believe it is important to have views presented freely and defer decisions to the reader who is the ultimate judge.
