The self-deprecating image of man - an amalgam of Pascal's thinking reed and Falstaff's forked radish - that provides a title for Peter Medawar's autobiography stems from his belief that the professional lives of scientists usually make dull reading. Sir Peter Medawar is a scientist of world renown, a member of the Royal Society and a Fellow of the British Academy. He won a Nobel Prize in 1960 for work that formed the basis of modern immunology and organ transplantation. He also wrote a series of essays: Pluto's Republic, and two books: Advice to a young scientist and The limits of science. He was awarded the order of merit in 1981. He describes this autobiography, loosely modelled on Coleridge's Biographia Literaria, as a book of opinions which my life may be regarded as a pretext for holding. He covers his early years in Rio de Janeiro, Oxford in the 1930s, illness and recovery and his work in a wide variety of institutions around the world.