We are deeply grateful to the many colleagues who provided unpublished information or examined parts of the text and helped improve its accuracy and completeness. Unpublished sources are acknowledged by citation in the References section. Those who reviewed entries in their areas of specialization are too numerous to name. Mary Anne Nelson was especially helpful in providing new EST and RFLP information from the University of New Mexico Genome Project. We thank Dorothy Newmeyer for continued encouragement and advice. Previously unpublished diagrams or photographs have been contributed by Barry Bowman (Fig. 66), David Catcheside (Fig. 57), Marta Goodrich-Tanrikulu (Figs. 17 and 18), George Marzluf (Fig. 50), Tom Schmidhauser (Fig. 7), and Matthew Springer (Figs. 14, 23, 28, 29, 35, 58, and 60). Photographic prints of previously published figures were made available by Ross Beever, Ramesh Maheshwari, N. B. Raju, and Matthew Springer.
     Work in our laboratories was supported by Grants AI-01462 and K6-GM-4899 from the National Institutes of Health and MCB-9728675 from the National Science Foundation to D.D.P., Grants GM-47498 from the National Institutes of Health and MCB-9630910 from the National Science Foundation to M.S.S., and grants from the UK Biotechnical and Biological Sciences Research Council to A.R.