The first of 14 chapters addresses the prevalence of opium use in the United States based on State surveys and clinical studies conducted between 1867 and 1923. This is followed by a chapter on the evolution of opium use as a health, social, and legal problem. The third chapter reviews the causative factors (etiology) of "chronic opium intoxication," based largely on the clinical knowledge of medical professionals who have reported on their personal experiences in dealing with chronic opium users between 1871 and 1925. The lack of comprehensive studies on the issue during this period is noted. General perspectives on the nature of chronic opium use and its effects during the period under study are reviewed in chapter 4, particularly as these perspectives affected control measures. Chapters 5 and 6 review current knowledge on the pathology (physical and mental effects) of chronic opium use, with attention to tolerance, dependence, and withdrawal. This is followed by a related chapter (Chapter 7) on "Symptomatology." This chapter reviews the physical and mental signs that a person is engaged in the chronic use of an opium product. Chapter 8 addresses the characteristics of opium users based on State and municipal surveys as well as clinical studies conducted in the late 19th to the early 20th centuries. Chapter 9 provides an overview of treatment characteristics for opium dependence during this same period. Subsequent chapters review international, national, State, and municipal controls for the opium problem. Appended supplementary information, an extensive bibliography, and a subject index