In December 1963, I received a letter from Kurt Jacoby, the Vice-President of Academic Press, telling me that Burnet had suggested to him that I should revise the second edition of his book, Principles of Animal Virology, which had been published in 1960. After discussions with Burnet, who said that he had switched to immunology and did not want to be involved, and considerable thought, I told Jacoby that I would not undertake a revision of Burnet's book, but would write a new book with much the same coverage, with the title, The Biology of Animal Viruses. After correspondence with many overseas virologists, it took me about two years to write, but eventually it was published in 1968 as a two volume book of 845 pages (excluding the subject and name indexes). It received excellent reviews and sold well enough for Academic Press to ask me to prepare a second edition. During the two years that I was writing this book, I did much less bench work than usual, and this influenced my decision to apply for the position of Director of the JCSMR when Hugh Ennor resigned in February 1967.