Geoffrey M. Cooper is Professor of Biology and Associate Dean of the Faculty for Natural Sciences at Boston University. Receiving a Ph.D. in Biochemistry from the University of Miami in 1973, he pursued postdoctoral work with Howard Temin at the University of Wisconsin, where he developed gene transfer assays to characterize the proviral DNAs of Rous sarcoma virus and related retroviruses. He then joined the faculty of Dana-Farber Cancer Institute and Harvard Medical School in 1975, where he pioneered the discovery of oncogenes in human cancers. Since moving to Boston University as Chair of Biology in 1998, Dr. Cooper has used The Cell in teaching undergraduate cell biology, as well as continuing his research on the roles of oncogene proteins in the signaling pathways that regulate cell proliferation and programmed cell death. He has authored two textbooks on cancer and published over 100 research papers in the field of cell signaling and cancer research. Robert E. Hausman was a Professor in the Department of Biology at Boston University. Receiving a Ph.D. in Biological Science from Northwestern University in 1971, he pursued postdoctoral work with Aron Moscona at the University of Chicago, where he investigated cell-cell interactions during early embryonic development. Dr. Hausman joined the faculty of Boston University in 1978, extending his investigations of cell surface interactions to muscle and nervous system development. He taught undergraduate cell biology with Dr. Cooper and contributed to several chapters of previous editions of The Cell.