This book is about the genetic gain in grain yield, yield components and quality traits in early and medium maturing varieties of soybean that was brought by public plant breeding efforts since 1974. It is based on field experiments conducted in 2009 at two locations in Ethiopia. The book reveals past improvements and their basis in different traits and indicates focus areas of future breeding efforts. It also gives a brief account of the status of yield plateau in soybean breeding in the country.