Nobel Prize Recipient. Max Delbrück, a German-born American physicist-turned-biologist, received international recognition after being awarded the 1969 Nobel Prize for Physiology or Medicine. He shared this coveted award with Alfred Hershey and Salvador Luria. The Nobel Prize committee gave these men the award "for their discoveries concerning the replication mechanism and the genetic structure of viruses." He developed a one-step process for quickly breeding bacteriophages or viruses that infect bacteria. In collaboration with Luria, he proved that after a bacterium has been infected, it can undergo spontaneous mutations that give it immunity to the bacteriophage. Working separately, experiments conducted by him and Hershey showed that genetic material from different kinds of viruses can mingle and produce new types of viruses, thus pioneering researching genetics. This process was previously believed to be limited to higher, sexually reproducing forms of life. In 1945 these scientists started a course in bacteriophage genetics at Cold Spring Harbor Laboratory on Long Island, New York. Born Max Ludwig Henning Delbrück, the youngest of seven children, his father was a college professor along with authoring a political column in a newspaper. His mother was the granddaughter of chemist, Justus von Liebig, the "father of the fertilizer industry." Prior to World War I, his family was among the affluent, well-to-do community. The community was destroyed during the war. After studying for short time astronomy at the University of Tubingen, he entered in 1924 the University of Berlin, but he received his BA degree from the University of Gottingen in 1929 and staying to earn a doctorate. After receiving his doctorate in 1930, he traveled to England, Switzerland, and Denmark, learning new languages and cultures along with meeting other scientists. From 1930 to 1932, he studied at Bristol University in England on his first Rockefeller Foundation Fellowship. In 1932 he relocated to Berlin for a research position at the Kaiser Wilhelm Institute. The politics of his homeland was changing as Nazi Germany was coming to power. He became part of a research group headed by Nikolaj W. Timofeeff-Ressovsky, a Russian researcher of genetics. Out of this group came a 1935 paper by Timofeeff-Ressovsky, K. G. Zimmer, and Delbrück on mutagenesis, which was published in 1945 by 1933 Nobel Prize in Physics recipient Erwin Schroedinger in his book "What is Life?" He published a paper in 1933 on gamma ray's scattering by a Coulomb field's polarization of a vacuum, and twenty years later, his research was confirmed by another scientist, naming it "Delbrück Scattering." He fled Germany for the United States in 1937 for political reasons, obtaining a position at the California Institute of Technology on a second Rockefeller Foundation Fellowship. During World War II, seven members of his extended family, who remained in Germany, were executed in the summer of 1944 as members of the Nazi Resistance, who were plotting the assassination of Nazi Germany's dictator Adolph Hitler, and two of his brothers-in-law were killed by looting soldiers in the last days of the war. He became a naturalized United States citizen in 1945. From 1939 to 1947, he taught physics at Vanderbilt University in Nashville, Tennessee. In 1947 he returned as a professor to the California Institute of Technology, remaining until 1976 when he retired as a Professor of Biology emeritus. In 1941, he married Mary Bruce, and the couple had two sons and two daughters. He coined the phrase, what he called "the Principle of Limited Sloppiness", which suggests that researchers should be "sloppy enough so that unexpected things can happen, but not so sloppy that we can't find out that it did." Named in his honor, the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC) for research is located in Berlin, Germany. Besides the Nobel Prize, he was honored with being elected as a Foreign Member of the Royal Society of London in 1967, elected as a member of the European Molecular Biology Organization in 1970, and since 2006, the American Physical Society awards the Max Delbruck Prize. In 1964 he received the Kimber Gold Medal and Award in Genetics from the United States National Academy of Sciences, which is considered the "Nobel Prize of Genetics." On August 26 to 27, 2006, his family and friends met at the Cold Spring Harbor Laboratory to celebrate what would have been his 100th birthday. Some of his genetic theories were later proven untrue with the discovery of DNA.