Billy N. Day was born in Arthur, West Virginia on October 23, 1930. He received B.S. and M.S. degrees from West Virginia University in 1952 and 1954, respectively, and a Ph.D. degree from Iowa State University in 1958 under the guidance of Robert M. Melampy. Day joined the faculty of the University of Missouri in 1958 as assistant professor and has been at Missouri since that time. He was promoted to associate professor in 1963 and to professor in 1968. He spent the 1965-66 year on sabbatical leave with Chris Polge at the ARC Unit of Reproductive Physiology and Biochemistry in Cambridge, England. Day has established himself as a top research scientist in reproductive biology. His general approach has been to investigate basic mechanisms involved in control of reproductive processes in farm animals, and then to use the basic knowledge to develop management techniques to increase reproductive efficiency in farm animals, with emphasis in swine. His recent interests have been directed toward establishment of an efficient system for in vitro production of porcine embryos. Although efficient in vitro embryo production had been achieved in cattle, progress in pigs was limited by a high incidence of polyspermy, a reduction of male pronuclear formation and a low rate of early embryonic development. Day has succeeded in reducing these problems by modifying culture conditions during in vitro maturation of oocytes and in vitro fertilization. Now, his group has an efficient system for in vitro production of porcine embryos and has achieved a high rate of blastocyst formation and successful pregnancies. Billy Day has published 196 refereed publications and 190 abstracts. He and his colleagues have published, have in press, or have submitted 58 refereed journal articles from 1996 to the present time. He has obtained over $4,600,000 in extramural funding as PI or Co-PI during his tenure at Missouri, including over $3,600,000 since 1985. Day was named the Fred F. McKenzie Distinguished Professor of Animal Reproduction in 1997. Bill has received numerous awards including the Animal Physiology and Endocrinology (1982) from the American Society of animal Science and was named a Fellow (1993) by the Society. Bill and his wife, Annabelle, have 5 children, 7 grandchildren, and 1 great-grandchild.