Seed dormancy is an adaptation to environmental changes that plants acquire during long-term phylogenesis. Dormancy may ensure that the species can survive natural catastrophes, decrease competition between individuals of the same species, or prevent germination out of season. Here, we review a classification scheme of seed dormancy; its development and continuum, regulation and evolution; as well as proteins associated with the induction, maintenance and release of dormancy. We also describe topics for future study of seed dormancy.