Mitosis is acell-cycle stage during which condensed chromosomes migrate to the middle of the cell and segregate into twodaughter nuclei before cytokinesis (cell division) with the aid of a dynamic mitotic spindle. The historyof mitosis research is quite long, commencing well before the discovery of DNA as the repository of genetic information. However, great and rapid progress has been made since the introduction of recombinant DNA technology and discovery of universal cell-cycle control. A large number of conserved eukaryotic genes required for the progression from early to late mitotic stages have been discovered, confirmingthatDNAreplicationandmitosisarethetwomaineventsinthecell-divisioncycle.Inthis article, a historical overview of mitosis is given, emphasizing the importance of diverse model organisms that have been used to solve fundamental questions about mitosis.