Vertebrate Virus Subcommittee International Committee on Taxonomy of Viruses 25 January 1984 Dear Harold: Thank you very much for your prompt reply to my request for news about your Retroviridae Study Group. I know I was peremptory in my request, more than you deserve, but I got results! Unfortunately, I must take issue with the main point in your letter. This concerns the taxonomic work that you and your colleagues have put into RNA Tumor Viruses. (When you mention a "new edition", I assume you mean the 1982 volume, since you can't be working on an even newer edition already.) The problem for you and me and the ICTV is that Chapter 2 of that book, pages 25 to 207, "Taxonomy of Retroviruses", is not an official ICTV publication. Indeed, to my knowledge, it hasn't seen any ICTV review. As retrovirologists, you and Natalie Teich and your associates have done your colleagues a tremendous service. But the Retrovirus Study Group of the ICTV still has a job to do for the rest of us in the biological community. Those 183 pages in Chapter 2 of RNA Tumor Viruses should be boiled down to the 6 to 12 pages that usually accommodate an Intervirology "Virus Characterization Data" article. Taxonomic proposals, which can come later, are formal versions, passed through the ICTV machinery, of ideas about classification that Intervirology articles on taxonomy throw out for discussion and reflection. Now, I am aware that you are an extraordinarily busy man and I do not expect taxonomy to be far from the bottom of your priorities list. As a solution, I would suggest that you identify a person who will carry the ball in your stead, perhaps Natalie Teich. I can relieve you of the responsibility of chairing the Retroviridae Study Group whenever you like. However, if you want to step down, I would appreciate very much your identification of a successor. Of course, I would be delighted if you would be willing to stay on and steer the Study Group through its ICTV activities. I just don't want you to feel trapped for three more years in a role that is more demanding than you have time for. Fair enough? With best regards, David W. Kingsbury, M.D.