Each step in a human's development - from the creation of the brain and heart to the formation of the fingers and toes - is carefully regulated. During the approximately 264 days from fertilization to birth, a single cell gives rise to many cells, which take on specialized characteristics, and the group of cells that is the maturing human will take on form and pattern. ""Human Development"" examines the significant, well-understood events that take place during this intricate process. This fascinating title also discusses how the study of model organisms has aided our understanding of a human's creation and what happens when something is altered during the normal course of events.