Jonathan M. Horowitz was born in Brooklyn, New York. His father was a food photographer and his mother a housewife who later returned to work for a foundation. His family was "culturally" Jewish; their holidays were celebrated mostly with food rather than religious ceremonies. From an early age Horowitz was interested in science, particularly in "small things"; by high school age he had decided to obtain a PhD and become a researcher in molecular biology, á la Francis Crick. He attended a new—and at that time trendy—high school where there were no competition, no sports, no grades; there he even designed his own courses. Following what he describes as a "common theme" in his life, namely no planning, he decided to go to Brown University because someone he knew was a student there. She told Horowitz that Brown was unstructured, so he could skip classwork and just do research in a lab. At Brown, having to take classes after all, he struggled during his first year and was given a last chance to do well. He did finish, but with a poor grade point average. During his last year he took an ultrastructure class, in which he worked with Lloyd Matsumoto, an electron microscopy expert in Peter Shank's lab. Horowitz says that his main accomplishment in that lab was to have met his future wife, who was working there as a technician. For graduate school, Horowitz was accepted at University of Wisconsin and at Johns Hopkins University. Not having investigated very much, he "asked around" as to which school he should attend. The brother of someone down the hall from Horowitz's lab ran a lab at Wisconsin, so Horowitz decided to go to Wisconsin. There he began with a rotation with Howard Temin; the rotation did not work out well, so Horowitz went to Rex Risser's lab to work on mouse retroviruses, notably strains of leukemia. When his wife accepted a job at Harvard, Horowitz had to find a postdoc in the Boston area. Shifting his interest from retroviruses to oncogenes, he again "asked around" and was referred to Robert Weinberg's lab at the Whitehead Institute for Biomedical Research. Originally working on ras protein, he eventually switched to Rb, sequencing the Rb gene and trying to develop antibodies against it. In collaboration with Edward Harlow Horowitz discovered that Rb is an E1A-binding protein and mapped the E1A- binding region on Rb. Finishing their postdocs, Horowitz and his wife had to find a place where both could have jobs. Horowitz's wife found a position at North Carolina State College of Veterinary Medicine, and Horowitz accepted an assistant professorship at Duke University. There he spent much of his time seeking support for his research. Duke's commitment to cancer research was hardly unwavering, and Horowitz's identity as a molecular cancer biologist counted against him in the tenure decision. When he was not granted tenure he accepted an associate professorship at North Carolina State College of Veterinary Medicine; here he finds much more support for his research, though he is still establishing his lab. He continues to work with the Rb gene; to seek funding; to publish; and to balance his work with his wife and two children.