The Organon Symposia have actually become a tradition, keeping up with exciting developments in reproductive medicine. The purpose of this symposium on "Fertiliza­ tion of the Human Egg in Vitro" was to bring together the stilllimited number of elinical specialists in the field and to stimulate another group of basic research people to exchange their experiences and knowledge, hopefully promoting elose cooperation between the two groups. It was a kind of scientific "first" that all research teams so far successful in achieving the birth of a healthy baby, fertilized in vitro came together at a workshop conference without a large audience of spectators and reporters, but with a small number of highly critical colleagues from the fields of basic reproductive physiology and comparative developmental biology. This atmosphere allowed for the elose exchange of results, hypotheses, diagnostic and therapeutic procedures, criticism, and respect, and created very productive discussions, all of which furthered the aim of the method: To help more childless couples to have their own babies by the ultima ratio procedure of in vitro fertilization and embryo replacement. The book that has emerged from this symposium will help to disseminate the great amount of information and experience gathered among the scientifically and clinically interested colleagues of many other hospitals and universities who could not be invited to the meeting. At the same time, it will prove that there is much more work to be done in the basic and clinical sciences of human embryology and reproductive biology.