Embryology is an old but fascinating subject. From the morphological observation of chick embryo development to the unravel of the molecular control of embryonic development in a variety of organisms, we have gone a long way. However, the more we learn the less we know. It is a miracle to see how a single cell develop into a fully functional adult. This course is design to build the ground for students with interest in embryology. We will discuss the basic principles and molecular controls of embryonic development. In particular, we will emphasize the progression from immature gametes, fertilization, cleavage to gastrulation (i.e. the formation of gut). The cell fate and embryonic axis formation will also be included. The popular experimental models used by current developmental biologist will be examined in detail.