This study is in some ways so unusual and provocative that the writer thinks it desirable to state here very briefly how the book came to take its present form. In one sense it could have taken no other, for it is essentially a confession, the inner story of a man who originally set out to write one kind of book and found himself compelled by the sheer force of circumstances to write another. It is not that the facts themselves altered, for they are recorded imperishably in the monuments and in the pages of human history. But the interpretation to be put upon the facts underwent a change. Somehow the perspective shifted --not suddenly, as in a flash of insight or inspiration, but slowly, almost imperceptibly, by the very stubbornness of the facts themselves. The book as it was originally planned was left high and dry, like those Thames barges when the great river goes out to meet the incoming sea. The writer discovered one day that not only could he no longer write the book as he had once conceived it, but that he would not if he could. To tell the story of that change, and to give the reasons for it, is the main purpose of the following pages.