I have been privileged to witness and participate in the great growth of knowledge on chemical carcinogenesis and mutagenesis since 1939 when I entered graduate school in biochemistry at the University of Wisconsin- Madison. I immediately started to work with the carcinogenic aminoazo dyes un- der the direction of Professor CARL BAUMANN. In 1942 I joined a fellow graduate student, ELIZABETH CA VERT, in marriage and we soon commenced a joyous part- nership in research on chemical carcinogenesis at the McArdle Laboratory for Cancer Research in the University of Wisconsin Medical School in...