Leopold Ruzicka worked in what he referred to as the "borderland" between bio-organic chemistry and biochemistry. His studies of odorous natural products led to his discovery of carbon rings with many more carbon atoms than had been originally thought possible. His research also contributed important information on how living things biosynthesize some steroids and sex hormones. For this work he shared the 1939 Nobel Prize in chemistry.

Leopold Stephen Ruzicka was born on September 13, 1887, to Stjepan and Amalija (Sever) Ruzicka. He was the first of two boys. They lived at first in Vukovar in Eastern Croatia (later part of Yugoslavia). His father, a cooper, died when Ruzicka was about four years old, and the family then moved to Osijek to live with relatives. Ruzicka attended elementary and high school in Osijek, where he received a classical education (Latin and Greek), and was initially determined to enter the Catholic priesthood...