Convicts represent those wrong-doers who have taken to a particular form of wrong-doing punishable by law. Of the larger army of bad men they represent a minority, who have been found out in a peculiarly unsatisfactory kind of misconduct. There are many men, some lying, unscrupulous, dishonest, others cruel, selfish, vicious, who go through life without ever doing anything that brings them within the scope of the criminal code, for whose offences the laws of society provide no punishment… We must be content to study in the microcosm of ordinary crime those instincts, selfish, greedy, brutal which, exploited often by bad men, have wrought such havoc to the happiness of mankind. It is not too much to say that in every man there dwell the seeds of crime; whether they grow or are stifled in their growth by the good that is in us is a chance mysteriously determined. As children of nature we must not be surprised if our instincts are not all that they should be. – From the Introduction of this book, originally published in 1918.