“The Brown Robin.” This letter Nick Carter found in his mail one morning a short time ago, on coming to his breakfast table. He read the letter with some interest, noting that it had been mailed late the afternoon before, and in the sub-district in which he lived. Tossing it over to his wife, Edith, to read, he said: “That might be taken for a challenge, I suppose.” Edith read it, and replied that she should take it for an impertinence. “Who is the Brown Robin?” she asked. “Ah! That is the great mystery,” answered Nick. “A woman?” asked Edith. “When you ask that question in that way,” replied Nick, “you mean to make the statement that you believe it to be a woman.” “Well, yes; I judge the writer of this is a woman.” “Why?” “The writing, in the first place.” “That will hardly do. It might be taken for the writing of a woman a little more masculine than is usual, or of a man a little more feminine than is usual. I carefully examined the writing before I gave you the letter, and could not determine satisfactorily to myself which it was.” Edith again examined the letter, and said that she should be afraid, after a second look, to stand on either side. “The truth is, Edith,” said Nick, “it is an assumed hand, not the natural one of the person who wrote it, and is not always employed by that person. That is my belief.” Again Edith studied the letter. “There is something about the whole thing,” she said, “that impresses me with the notion that the writer of this is a woman. But if you were to ask me why, I could not tell you.” Nick laughed. “It is the same old story of puzzling mystery.” “Then you know something of the Brown Robin?” “I know that the Brown Robin puzzled and mystified the police of Chicago two winters ago. I was appealed to then to go to Chicago, take up the case, and ferret out the mystery, but then I was engaged in an important matter here and could not go. “Suddenly the Brown Robin disappeared from Chicago and turned up in Boston, where the police were put at their wits’ end in an endeavor to detect the person. “As suddenly he, she or it flitted to Philadelphia, with a like result, and then back again to Chicago. Now it would seem that the Brown Robin is making New York its roosting place.” “But who is the Brown Robin, and what does it do?” “As I said, who the Brown Robin is—whether a he, she, or it—is a mystery. What the Brown Robin does is to extort money from various kinds of people, and most successfully, by blackmail. “The Brown Robin moves about so skillfully and shows up in so many guises, that he, she or it has always escaped detection, and has left the police of each place where it has operated in doubt whether it is a man, or a woman, or a lot of men and women, moving under the directions of a very skillful person. “That is all I can tell you, for I have not looked deeply into the matter.” “This is a direct challenge to you.”