Unlike most biomedical scientists, Burnet wrote many books as well as scientific papers. Early in 1948, after he had an opportunity to evaluate my writing, Burnet asked me to collaborate with him in an article he had been asked to write for a new international journal, Heredity (Burnet and Fenner, 1948). He must have been satisfied with my performance, because he then asked me to collaborate with him in producing a second edition of The Production of Antibodies, the first edition of which he had published in 1941 (Burnet et al., 1941). I helped chase up some of the work done since then, notably Medawar’s studies of transplantation immunity. Burnet was responsible for all the interpretation and speculation. The second edition is notable because it contains the first mention of the concept of immunological tolerance, the topic cited in the award of the Nobel Prize to Burnet and Medawar in 1960.