Roger E. Karess and his two older sisters grew up in Great Neck, New York. Their grandparents were Jews from Eastern Europe, and their neighborhood consisted of other family members and people with similar backgrounds. Karess's father had a law degree but did not practice; he worked in a family business for many years and then was in insurance. His mother was a homemaker. Both parents were adamant that all three children would go to college. The older sister is a chemist in industry; the younger, after a dancing career, became a social worker. Karess discusses his upbringing as a Reform Jew; Europeans' attitudes toward Americans; racism and anti-Semitism in Europe; Karess' Jewish identity; and Roman Catholic influences on contemporary France. Karess cannot remember not being interested in science. He enjoyed the experiments in elementary school and reading the life stories of great scientists in Paul de Kruif's Microbe Hunters. His fourth-grade teacher noted his "passion" for science. In high school he took advanced science courses, and he attended a summer program for high school students at Jackson Laboratory; there he studied the effects of heavy metals on mouse embryo development and was introduced to reading scientific articles. He also attended a high-school science program at Columbia University. He was accepted at Yale University where he worked in David Ward's lab studying paroviruses. He talks about the difference between liking science and doing science; about his regret at not having taken more lab classes at Yale and about having taken courses in medieval Latin and art history. He developed an interest in tumor viruses and wrote a class paper on host virus restriction. He talks more about working in the Ward lab; about having worked on reverse transcriptase in the Ted Reid lab; and about letters of recommendation he received from Yale professors. He entered graduate school at Rockefeller University; he began early in Vincent Allfrey's lab so as to gain more lab experience. He then transferred to the Hidesaburo Hanafusa lab to study retroviruses. Here he discusses changes in his confidence as a scientist over time; his evaluation of himself as an undergraduate researcher; undergraduates in his own lab; his performance on his senior exam; his reasons for selecting Rockefeller for graduate school; Rockefeller's unstructured program; and playing softball at Rockefeller with Mark Rieman and jogging with Michael Greenberg. He goes on to describe Hanafusa as a teacher and a mentor and Hanafusa's research on tumor viruses. Karess himself sought to identify the RNA binding site for retroviruses but was thwarted by technical difficulties. Karess then talks about how William Hayward distinguishes between transformation-competent and transformation-defective virus cells; how Peter Duesberg's radiolabeling of viral RNA helps demonstrate the existence of an oncogene; Hanafusa's research on proto-oncogenes; how Karess seeks to isolate the src protein; and Raymond Erikson's discovery that src is a kinase. Karess was challenged in his attempt to identify the first known kinase and unable at the time to discover the fps oncogene. This leads to an explanation of the factors involved in scientific breakthroughs and the need to interpret data with fresh, objective eyes. He evaluates his self-confidence at the end of his doctorate. Here Karess gives his opinion on the constructive and destructive effects of competition in science and the need to take risks in research. He goes on to compare the structures of scientific research in France and the United States; the advantages and disadvantages of doing research in France; and the relative prestige of publishing in American and European journals. Karess accepted a position as a principal investigator at the Centre de Génétique Moléculaire (CGM) near Paris. When he published an article in Cell he encountered the politics of scientific publishing. He goes on to describe funding in France; the Centre National de la Recherche Scientifique (CNRS) and setting up a lab at CNRS; and his own funding. More discussion of the funding of scientific research in France leads to a discussion of Karess's funding in the United States and his opinion about the need for reforms in the way science is done in both France and the United States. Karess's research interests shifted from oncogenes to Drosophila genetics, and he developed an interest in transposable elements. He accepted a postdoc position in the Gerald Rubin lab at the Carnegie Institution of Washington, where he studied unstable alleles in Drosophila. Rubin's discovery of P elements revolutionized Drosophila genetics. Karess analyzed P transposable element function. He then accepted a second postdoc position in David Glover's lab at Imperial College of Science and Technology, University of London. He talks about trends in assigning names to Drosophila genes and the names Karess and others created. Karess applied for his first academic position and accepted an offer from New York University. Here he discusses the people in his own lab. He took up studying Leishmania. Karess moved his lab to the CGM in Paris, where he has been studying the rough-deal gene. Karess concludes with an assessment of his scientific research.