this book comes from the reflections and experience of more than forty years spent in court. aside from the practice of my profession, the topics i have treated are such as have always held my interest and inspired a taste for books that discuss the human machine with its manifestations and the causes of its varied activity. i have endeavored to present the latest scientific thought and investigation bearing upon the question of human conduct. i do not pretend to be an original investigator, nor an authority on biology, psychology or philosophy. i have simply been a student giving the subject such attention as i could during a fairly busy life. no doubt some of the scientific conclusions stated are still debatable and may finally be rejected. the scientific mind holds opinions tentatively and is always ready to reexamine, modify or discard as new evidence comes to light.

naturally in a book of this sort there are many references to the human mind and its activities. in most books, whether scientific or not, the mind has generally been more closely associated with the brain than any other portion of the body. as a rule i have assumed that this view of mind and brain is correct. often i have referred to it as a matter of course. i am aware that the latest investigations seem to establish the mind more as a function of the nervous system and the vital organs than of the brain. whether the brain is like a telephone exchange and is only concerned with automatically receiving and sending out messages to the different parts of the body, or whether it registers impressions and compares them and is the seat of consciousness and thought, is not important in this discussion. whatever mind may be, or through whatever part of the human system it may function, can make no difference in the conclusions i have reached.

the physical origin of such abnormalities of the mind as are called "criminal" is a comparatively new idea. the whole subject has long been dealt with from the standpoint of metaphysics. man has slowly banished chance from the material world and left behavior alone outside the realm of cause and effect. it has not been long since insanity was treated as a moral defect. it is now universally accepted as a functional defect of the human structure in its relation to environment.

my main effort is to show that the laws that control human behavior are as fixed and certain as those that control the physical world. in fact, that the manifestations of the mind and the actions of men are a part of the physical world.

i am fully aware that this book will be regarded as a plea or an apology for the criminal. to hold him morally blameless could be nothing else. still if man's actions are governed by natural law, the sooner it is recognized and understood, the sooner will sane treatment be adopted in dealing with crime. the sooner too will sensible and humane remedies be found for the treatment and cure of this most perplexing and painful manifestation of human behavior. i have tried conscientiously to understand the manifold actions of men and if i have to some degree succeeded, then to that extent i have explained and excused. i am convinced that if we were all-wise and all-understanding, we could not condemn.

i have not thought it best to encumber the book with references and foot-notes, for the reason that statistics and opinions on this subject are conflicting and imperfect, and the results after all must rest on a broad scientific understanding of life and the laws that control human action. although the conclusions arrived at are in variance with popular opinions and long-settled practice, i am convinced that they are old truths and are in keeping with the best thought of the time.

i am aware that scientifically the words "crime" and "criminal" should not be used. these words are associated with the idea of uncaused and voluntary actions. the whole field is a part of human behavior and should not be separated from the other manifestations of life. i have retained the words because they have a popular significance which is easy to follow.

clarence darrow.

chicago, august 1, 1922.