'What about that curious feeling that nearly everyone has now and then experienced - that sudden, fleeting, disturbing conviction that something which is happening at that moment has happened before? What about all those dreams which, after being completely forgotten, are suddenly, for no apparent reason, recalled later in the day? What is the association which recalls them? Was it possible that these phenomena were not abnormal, but normal? It was absolutely inconceivable that a thing of this sort, if true, could have managed to escape, through all these centuries, universal perception and recognition.' - J W Dunne. This book about the perfectly normal ability to see the future created a national commotion in the 1920's.