George Kistiakowsky (1900 - 1982)
Born in Russia in 1900, he received his Ph. D. in Chemistry in 1925. Upon moving to the United States, he joined the faculty at Harvard.
Kistiakowsky joined the Manhattan Project in late January 1944. Under his leadership, they were able to develop the complex explosive lenses needed to compress the plutonium sphere uniformly to achieve critical mass.