What a din along the boulevards on the day when the newsboys shouted: "Arrest of Arsène Lupin!"My excuse for duplicating reports that we all heard from the newsboys is that I can supply something new: I can furnish the key to the puzzle. There is always a certain mystery about these adventures: I can dispel it. I reprint articles that have been read over and over again; I copy out old interviews: but all these things I rearrange and classify and put to the exact test of truth. My collaborator in this work is Arsène Lupin himself, whose kindness to me is inexhaustible. I am also under an occasional obligation to the unspeakable Wilson, the friend and confidant of Holmlock Shears. (For this is the adventure where Arsène Lupin and Holmlock Shears came face to face. And a thrilling adventure it is.)