Seeds are the delivery system for improved cultivars to the consumer. Thus, high physiological seed quality is essential for the attainment of an acceptable plant population in the field or greenhouse. High germinating seed lots may differ substantially in field emergence when sown at the same time in the same environment. These differences are caused by another important measure of seed quality, seed vigor. This CD defines the concept of seed vigor as it relates to germination, describes the types of seed vigor tests and relates to the usefulness of seed vigor to the farmer and seed industry. It is intended to educate seed analysts, seed professionals, students and the consumer regarding the important implications of seed vigor to the seed industry and the farmer.