This is the first dedicated, in-depth account of trophoblast: the tissue derived from the fertilized egg that nourishes and protects the developing fetus. The cells of the trophoblast have many unique qualities, and exhibit great variability across different species. It has a fascinating role in the development of the placenta and as a regulator during early growth of the embryo. These aspects are all fully covered as well as studies on why it is not rejected by the mother as 'foreign' tissue. This volume provides an up-to-date summary of the state of current knowledge and offers some glimpses as to future development on the scientific and clinical front.