Stem Cells reviews the current knowledge on stem cell science covering all its major topics, from basic cell biology to legislation. Volume II concentrates on mechanisms of stem cell regeneration in the adult organism with the aim to understand how lost tissue can be replaced during adulthood and aging. The second focus of this volume is on stem cell identification and manipulation, including applications in basic research, medicine, and industry. Volume II closes with an outlook on generalized approaches to solve legislative and ethical challenges.