Technical Abstract: Major M. Goodman is the leading expert on the classification and use of the diverse genetic resources of maize. He pioneered the development and use of mathematical approaches to classification of diverse plant materials; had a primary role in the development of one of the first comprehensive plant genetic marker systems; championed the maintenance, evaluation, and use of gene bank resources for crop improvement; and to this day conducts a very productive applied public maize breeding programs. His impact on the scientific community has increased as understanding of genetic diversity and its relationship with phenotypic diversity has become a major objective of large-scale plant genomics efforts (Buckler et al., 2006). Maize plays a key role in these efforts thanks in part to the groundwork that Major Goodman developed to elucidate and synthesize the relationships among the bewildering array of diverse maize seed resources. As former students of Dr. Goodman, we dedicate this chapter to an outstanding mentor and a model of scientific vigor and integrity, on behalf of all of his colleagues and former students.