Berlin is all about volatility. Its identity is based not on stability but on change.

Berlin inspired Bowie and stirred him to write about real, important matters.

Eight months after graduating from Ryerson, there I was in West Berlin working with Marlene Dietrich and David Bowie and Kim Novak.

Bricks and mortar Berlin has become a kind of network across which visitors and residents interact as if on some sort of comfortable global platform.

To me, Berlin is as much a conceit as a reality. Why? Because the city is forever in the process of becoming, never being, and so lives more powerfully in the imagination.

The travel book is a convenient metaphor for life, with its optimistic beginning or departure, its determined striving, and its reflective conclusion. Journeys change travellers just as a good travel book can change readers.