Quantitative and qualitative trends in crime internationally are noted, and the impact of technical progress on criminal investigation is considered. The influence of emphasis on the protection of suspects' rights upon criminal investigation is also examined. In portraying the techniques and stages of criminal investigation, sections are devoted to informers, surveillance, wiretapping, suspect identification (lineup, video film, criminal histories, and recognition from physical characteristics), preventive investigation, and collecting evidence. Brief attention is also given to questioning and confessions. A discussion of investigative organization and structures covers specialization and continuous training, the female crime investigator, crime investigators and the media, centralizing and circulating information, the territorial scope of police departments, the international dimension of crime investigation, and the crime prevention aspects of investigation. Twelve footnotes are provided.