Hans C. Oettgen was born in Cologne, Germany, spent some time in Nairobi, Kenya, but was raised mostly in New Canaan, Connecticut, the eldest of three children. His mother was a teacher; his father was a researcher in immunology and a physician in internal medicine who, eventually, worked at Memorial Sloan-Kettering Cancer Center in New York City. Oettgen enjoyed school, especially math, reading, and spending time outdoors. His family often went camping in the Adirondacks and spent summers traveling by train and/or by boat throughout Europe. He had a chemistry set though his interest in math led him more towards computer programming than performing experiments. He spent time in his father's lab during his childhood, but in high school he worked in some of his father's colleagues labs, mostly doing technical work without understanding the fundamental scientific questions being investigated, until he had the chance to do research involving the isolation of a particular protein from peanuts, called peanut lectin, which binds to a sugar structure and is expressed on some cancer malignancies. He was also in the Boy Scouts of America, was (and is) an avid photographer, and knew that he wanted a broad liberal arts education even though he intended to pursue science or medicine as a career. Oettgen matriculated at Williams College, majoring in chemistry, but ultimately choosing to attend medical school. He began his medical studies at the Harvard Medical School; the summer after his first year, though, gave him the chance to work with Cornelius P. Terhorst at the Dana-Farber Cancer Center conducting research on B lymphocytes, using protein chemistry to describe B-1 and B-2. While at Harvard he decided to move into the MD/PhD program and continued to work with Terhorst, writing his thesis on the biochemical characterization of T-cell-receptor structure. After completing his residency in 1990, Oettgen was slotted to undertake a postdoctoral fellowship with David Baltimore at the Whitehead Institute, but Baltimore's move to Rockefeller University in New York City prompted Oettgen to do his fellowship with Philip Leder in genetics. As a postdoc he developed a mouse without the gene for immunoglobulin E (IgE). He then accepted a position at Children's Hospital in Boston, Massachusetts, researching the role of IgE in immune function. At the end of the interview Oettgen talks about the process of writing journal articles; balancing family and career; his leisure activities; the source of his ideas; and the impact of technology on his work. He concludes the interview with a discussion of competition and collaboration in science; the grant-writing process; the role of the scientist in educating the public about science; the impact of the Pew Scholars Program in the Biomedical Sciences on his work; his children; and the benefits of having a clinical practice and doing basic science.