Hybridization and heterosis are discussed in relation to development of hybrid corn. Brief consideration is given to early investigations of Shull and East; then tests by the author are described whereby he was able to demonstrate to students some of the aspects of hybridization of corn. After considering relationship of his subject to "evolution." the author concludes, "If corn had developed from some 'simple' plant, such as an alga, it would necessarily have been by the introduction of many new and improved genes. Instead of introducing new genes, the remarkable process of making Zea mays more useful to man involves experts rejecting undesired genes and collecting other genes into more desirable groups".