In the fast pace and competitiveness of modern science, there is less and less time to teach students the background on how the currently used scientific methods and ideas came about. This fact is unfprtunate, for it is salutary to realize that many so-called discoveries and inventions are not new and that the old literature is replete with ideas. In doing our work we often stand on the shoulders of those who have gone before. The study of early mammalian development in vitro, which has undergone explosive growth since 1960, provides many illustrations of these facts. In addition, to minimize the tendency of investigators to “rediscover the wheel”, it is pertinent at this time to reflect on the roots of the field. The subject is closely intertwined with the history of embryo transfer (see Adams, 1982) and of in vitro fertilization [see Austin (1961) and Biggers (1984)].