Trophoblasts (from Greek trephein: to feed, and blastos: germinator) constitute a particular population of cells forming the outer layer of the blastocyst, providing the embryo with nutrients and giving rise to the outer chorionic sac and the fetal component of the placenta. The trophoblast facilitates embryonic implantation via its inner layer of mononuclear cytotrophoblasts and its outer layer of multinuclear cytoplasm, the syncytiotrophoblasts, forming the early connections between the embryo and the maternal endometrium. The cells of the trophoblast have many qualities, exhibit important functions and have an important role in the development of the placenta; also, they work as a regulator during early growth of the embryo. This volume provides a detailed summary of knowledge regarding the development of the trophoblast during the First Trimester of Pregnancy, the process of placenta apoptosis and the factors causing aging of the placenta. The pathology of trophoblast can manifest itself in several clinical conditions during pregnancy such as intrauterine fetal growth restriction (IUGR), gestational trophoblastic disease and pre-eclampsia. The analysis of the pathogenetic mechanisms involved in these critical conditions are discussed in this book. These aspects are analyzed with scientific methodology on the basis of updated studies. "Development of Human Trophoblast" can be considered a reference book for every pathologist, obstetrician and resident.