Considered both the founder of modern cellular immunology and its greatest theoretician, Niels K. Jerne shared the 1984 Nobel Prize for medicine or physiology with César Milstein and Georges J. F. Köhler for his body of work that explained the function of the immune system, the body's defense mechanism against disease and infection. He is best known for three theories showing how antibodies--the substances which protect the body from foreign substances such as viruses and poisons--are produced, formed, and regulated by the immune system. His theories were initially met with skepticism, but they later became the cornerstones of immunological knowledge. By 1984, when he received the prize, colleagues agreed that he should have been recognized for his important contributions to the field much earlier than he was. Jerne's theories became the starting point from which other scientists, notably 1960 Nobel Prize winner Frank Mac Farlane Burnett, furthered...