To the old saying that if you want to learn something about a subject, teach a course on it, I would add the much more arduous option of writing a book about it. The upside, of course, is that you may gain a perspective on a lo- time favorite subject which can be achieved in no other way. The fact is that the opportunity to write such a book as this is, indeed, a rare opportunity. This is especially so for someone who, by the calendar, is well into retirement years. While high T itself is the opportunity of a lifetime for those of us who c experienced it, and revisiting the old milestones in writing this monograph was a genuine nostalgia trip, it is also important to reffect on the purpose of such a book as this. Now that the great majority of experimental high-T c studies are—nished, who could be interested in such a book? To give some 2 1 kind of answer to this, let me pinpoint the 2006 M S Conference in Dresden.