The development of international cooperation in newborn screening and the efforts of Bob Guthrie and Horst Bickel.

After 1 started screening for phenylketonuria (PKU) in 1966, there were serious difficulties due to the lack of scientific information. There Lvere no relevant international meetings useful for a beginner. In 197 1, I was lucky to meet one of the major figures in our field, Horst Bickel. Due to his kindness. I was invited to an international symposiunl in Warsaw, Poland in 1972 where I met Robert Guthrie, Harvey Levy and many other pioneers in neonatal screening for metabolic disorders. Before the Warsaw meeting, there were intenlational conferences on screening for PKU and related disorders in Yugoslavia (I 966) and Israel (1969). These were supported by funding from the United States and were not open meetings. The proceedings of the meetings were not generally available worldwide.