WALTER E. KISIELESKI is an Associate Scientist in the Division of Biology and Medicine of the Argonne National Laboratory. He was formerly associate professor of chemistry at Loyola University in Chicago. His undergraduate studies were at James Millikin University in Decatur, Illinois, and his graduate studies were at the University of Chicago. He received an Honorary Doctor of Science degree from James Millikin University in 1962. In 1958 he was a delegate to the Second Atoms for Peace Conference in Geneva, Switzerland. He was visiting lecturer in the department of biochemistry at the University of Oslo in Norway in 1963. Dr. Kisieleski is shown operating an automatic windowless strip counter that scans paper chromatograms and thus locates labeled substances.

RENATO BASERGA was born in Milan, Italy, and received a medical degree from the University of Milan in 1949. He is presently research professor of pathology at the Fels Research Institute at Temple University Medical School in Philadelphia, and associate editor of the journal, Cancer Research. Formerly he was associate professor of pathology at Northwestern Medical School in Chicago, where he was the recipient of a Research Career Development Award from the National Institutes of Health.