Book excerpt: Introduction to Corrections provides a comprehensive foundation of corrections that is practitioner-driven and grounded in modern research and theoretical origins. This text uniquely illustrates how the day-to-day practitioner conducts business in the field of corrections in both institutional and community settings. Experienced correctional practitioner, scholar, and author Robert D. Hanser shows readers how the corrections system actually works, from classification, to security, to treatment, to demonstrating how and why correctional practices are implemented. Furthering the reality of the modern correctional experience, the Third Edition includes a new chapter on immigration detention centers.