This biography probes the unusual mind, the dramatic life, and the outstanding scientific work of Danish-born immunologist Niels Jerne (1911-1994). Jerne's Nobel Prize-winning achievements in the field of immunology place him in the pantheon of great 20th-century biomedical theorists, yet his life is perhaps even more interesting than his science. The volume tells Jerne's story, weaving together a narrative of his life experiences, emotional life and extraordinarily creative scientific work.