This chapter addresses two major technical aspects, classical genetics and traditional breeding, which are directly concerned with soybean cultivar development and germplasm enhancement. Today, most of the soybean cultivar development occurs in the private sector, while public sector breeders focus on germplasm enhancement, breeding methodology and molecular technology development, and education of students who become professional plant breeders. Continued enhancement of soybean cultivars relies on identification and genetic manipulation of novel desirable genes for adaptation to new environments, new management practices, and new end uses. Selection efficiency is largely dependent on specific traits of interest that are either qualitative or quantitative. While many agronomic traits, such as disease resistance, are simply inherited and easy to select for, yield is a polygenic and complex trait to manipulate. Several traits may be linked or correlated, which may be advantageous or deleterious to breeders in terms of selection. The traditional breeding scheme can be summarized in three basic steps: 1) selecting parents with desired characteristics and intercrossing them, 2) growing hybrid