This story is intended for three classes of readers, and no more. It
is intended for those who have to bring up children, for those who
have to bring up themselves, and for those who, in order that they
may think of bettering the weaker, are, on their own part, strong
enough to begin that task by bearing a knowledge of the truth.
For it is the truth only that I have told. Throughout this narrative
there is no incident that is not a daily commonplace in the life of
the underworld of every large city. If proof were needed, the
newspapers have, during the last twelvemonth, proved as much. I have
written only what I have myself seen and myself heard, and I set it
down for none but those who may profit by it.