Embryology can also identify risk factors for serious genetic conditions within the fertilized egg and select the most viable eggs for implantation. The study of embryology has led directly to the concept of cloning, either for a whole organism or parts of an organism. Cloning and in vitro fertilization have both been subject to tremendous debate. Part of the problem lies within each embryology textbook. They all state that life begins at the moment of conception. While it is true that some form of life begins at conception, the degree, value and quality of such a life is not addressed. The text integrates the descriptive, experimental and biochemical approaches into a conceptual framework for the analysis of development. All important points are illustrated diagrammatically. The title is not intended to be comprehensive nor could it be at length, but it concentrates as putting across the basic principles of the subject as briefly and lucidly as possible.