Profiles in Science, the National Library of Medicine Web site celebrating 20th century leaders in medical research and public health, added Virginia Apgar, MD, Harold Varmus, MD, and Michael Heidelberger, PhD, in 2006. This brings to 20 the number of outstanding figures whose personal and professional records and papers are on the site.

In 1949, faced with unacceptably high newborn mortality rates in her hospital’s maternity ward, anesthesiologist Virginia Apgar (1909-1974) set out to ensure that newborns in distress got the prompt attention they needed. Using the signs anesthesiologists monitor during and after surgery—heart rate, respiration, reflex irritability, muscle tone and color—she developed a simple, rapid method for assessing the condition of newborn babies. Quickly adopted by obstetric teams, the now famous Apgar scale reduced infant mortality and laid the foundations of neonatology.

Michael Heidelberger (1888-1991) was the founder of immunochemistry, the branch of biochemistry that examines the immune system of animals on a molecular level. His seminal discovery in 1923, with Oswald T. Avery (also featured in Profiles in Science), that powerful disease-causing antigens of pneumococcus bacteria are polysaccharides opened up an expansive new area in the study of microorganisms, and led to new understanding of infectious diseases, their treatment, and their prevention. “Heidelberger redefined immunology and founded it on the precise analytical basis of biochemistry,” commented Donald A.B. Lindberg, MD, Director of the National Library of Medicine.

Harold Varmus (born December 18, 1939) is a pioneering molecular biologist, cancer researcher, NIH Director, and 1989 Nobel Laureate in Medicine. With his long-time collaborator, J. Michael Bishop, Varmus theorized that cancer arises from certain genetic mutations.