I have been writing and revising this book for the past seven years, changing and transforming it many times, always for the same reason. After I had been able to express the abstract idea I had in mind I would reflect about it and discover that something deeper lay beyond. If professional demands had not obliged me to produce a fmal manuscript I would never have fmished the writing. If I had been asked to enumerate all the obstacles I faced whilst turning this book into print another and perhaps no less intriguing book would have resulted. I am aware of my good fortune in having fmally...