In this diverse synthesis of recent research, the regulation of growth in response to environmental and genetic stimuli is discussed in reference to tissues and cells, as well as the whole animal. Many issues are addressed in detail, including how hormones and growth factors regulate animal growth in the developing embryo and what processes at the molecular level determine the growth patterns of different tissues. The text draws contrasts between regulation in fetal and adult tissues, and among different tissues such as the CNS, bone and muscle. Functional chapters focus on the molecular links between mechanical tension and muscle growth, for example, while other chapters review the roles of specific molecules such as growth hormone.