The common potato, Solanum tuberosum L., is the third most important food crop and is grown and consumed worldwide. Indigenous cultivated (landrace) potatoes and wild potato species, all classified as Solanum section Petota, are widely used for potato improvement. Members of section Petota are broadly distributed in the Americas from the southwestern United States to the Southern Cone of South America. The latest comprehensive taxonomic treatment of section Petota was published by John (Jack) Hawkes in 1990; it recognized seven cultivated species and 228 wild species, divided into 21 taxonomic series. Since 1990, intensive field collections from throughout the range of the group, coupled with morphological and molecular studies, have halved the number of species and elucidated new ingroup and outgroup relationships. The recent sequencing of the potato genome has greatly accelerated investigation of all aspects of potato biology and allows us to address new questions not conceivable before. The purpose of this review is to provide a historical overview and update since 1990 of the systematics, diversity, genetics, domestication, evolution, and breeding of Solanum section Petota that will serve as a reference for the next generation of studies in the potato.