This book was not published for the purpose of displaying any literary ability I may possess, as I have never aspired to win fame by the wielding of a pen. Within its pages, however, I have attempted, in my own way and in my own manner, to make clear to the reader the inside or hitherto unpublished facts about some of the big cases I have handled during the fifty years I have made the prevention of crime and the tracking and punishment of criminals my profession. How well I have succeeded, I will leave it to the reader to judge.