Development is the complex process through which a single-celled embryo transforms into a multicellular organism. Developmental processes are guided by information encoded in an organism's DNA, and geneticists are trying to understand how this information leads to a fully formed organism. This video reviews seminal research in the field of developmental biology, including the identification of specific genes that control various embryonic processes. An introduction to the major questions asked by developmental geneticists, and the prominent methods used to answer them, is also provided. Finally, several applications of these prominent methods are discussed, in order to show specific experiments currently being performed in this field.