Nobel Prize Recipient, Scientist. He received world-wide acclaim for being the 1934 Nobel Prize for Chemistry. He discovered the heavy form of hydrogen known as deuterium, which led to the development of the atomic bomb. He also made fundamental contributions to the accepted theory of the origin of the Earth and other planets. He was the recipient of the prestigious Willard Gibbs Award from the Chicago Section of the American Chemical Society in 1934 and then wrote the entry on deuterium for the 1936 printing of the 14th edition of the Encyclopedia Britannica. Later in his life, he was a supporter of the teaching of science in public schools and was the recipient of the United States National Medal of Science in 1964, which was bestowed by President John F. Kennedy. Even after receiving the Nobel Prize, he continued to research isotopes of hydrogen, carbon, oxygen, nitrogen and sulfur, and writing papers on his finds. He was the editor of the “Journal of Chemical Physics” from 1933 to 1940 as well as being published in other professional periodicals. With the outbreak of World War II, he was active in the United States government’s program for separating the fissionable uranium isotope 235U from the more-abundant 238U for use in the atomic bomb. From 1940 to 1945, he was the Director of the War Research, Atomic Bomb Project, Columbia University in New York City. Although the Manhattan Project was a huge undertaking involving numerous scientists, he served on various advisory committees as a government employee. He was head of the project on diffusion, and when this research was dismissed, he did not continue with the project. He attempted to convince United States President Harry S. Truman not to use the atomic bomb on Japan, but failed. After the war, he became active as a civilian in the control of atomic weapons and proposed an international ban on production and stockpiling. At this point, he changed his subject of research. In 1945, he became a professor at the University of Chicago becoming involved with their solar system research. In 1952, he published his book “The Planets: Their Origin and Development,” which has been described as “the first systematic and detailed chronology origin of the Earth, Moon, meteorites and parts of the solar system.” His work continued with the solar system through the 1950s and 1960s. He ultimately influenced the United States National Aeronautics and Space Administration (NASA) to undertake the Apollo Program for lunar exploration. From 1956 to 1957, he was the George Eastman Visiting Professor at the University of Oxford in England, received an Honorary Doctorate Degree from Oxford, had received in 1940 the Davy Medal from the Royal Society in London and Honorary Fellow of the Chemical Society in London. He retired from the University of Chicago in 1958, but continuing his solar research, he became professor-at-large at the San Diego campus of the University of California. When Apollo II returned in 1969 with Moon rocks and dust, he was one of six scientists who was allowed to examine this matter, which showed some of his hypothesis about the moon were wrong and at this point, as an elderly scientist, he revised his reasoning based on this new evidence. He had a simple beginning as the son of Rev. Samuel Clayton Urey and Cora Rebecca Reinoehl. With his father dying when he was six years old, Harold Clayton Urey's mother remarried and had a total of five children. After graduating from high school, he taught public school for three years, first in Indiana and then Montana. While in Montana, he attended the University of Montana majoring in zoology and chemistry. He graduated in 1917 and found employment during World War I as a chemist, hence his scientific career began. After the war, he taught chemistry for two years at the University of Montana before starting the University of California at Berkeley receiving his doctorate with the dissertation on the energy levels of the hydrogen atom in 1923. With a American-Scandinavian Fellowship, he studied with Danish physicist and the 1922 Nobel Prize recipient, Niels Bohr at the Institute for Theoretical Physics in Copenhagen from 1923 to 1924. At this point in his career, he joined the faculty at Johns Hopkins University in Baltimore, Maryland teaching the importance of quantum mechanic and continuing his research on atoms and molecules. In 1930, he and Arthur E. Ruark published “Atoms, Molecules and Quanta.” In 1929, he relocated to continue his research at Columbia University in New York City adding the theory of isotopes to his research, and it was here that he got his first major break through in his discovery of deuterium, which led to the Nobel Prize. Through the years, he received numerous honorary degrees nationally as well as internationally and was recognized by many societies with professional awards. He married Frieda Daum and had four children. Suffering from Parkinson and cardiac disease, he retired in 1970.