Book excerpt: UNDERSTANDING STREET GANGS offers a unique and pioneering approach to the street and prison gang dilemma and provides both local and national perspective. This popular book is used by colleges, universities, and academies, and also for advanced officer training throughout the country. The authors are leading authorities on gang activities. No other book offers such insight or understanding into this escalating threat. It covers causative factors, family structure and profiles, socioeconomic pressures, and drugs. It also defines gangs, membership, structure and organization, communication, and measurements of gang violence, offers perspective on gang activity, and suggests possible solutions.