Since IVF led to the first successful birth over 40 years ago, it has transformed from a medical innovation focused on women with tubal occlusion to a far broader infertility and, in many instances, noninfertility therapy. The field of reproductive medicine today is nothing like what it was when it first started. As with many new technologies, the early decades were spent honing the craft, adapting laboratory and clinical innovations from animal experimentation to one that has provided a revolution in the development of complex hormonal treatments and laboratory practices (Chapters 2 and 3), including extended culture, ICSI, vitrification, and oocyte cryopreservation (Chapters 5 and 10).