Abu Ali Hasan ibn Ali Tusi (April 10, 1018 – October 14, 1092), better known by his honorific title of Nizam al-Mulk (Persian: ???????????, "Order of the Realm") was a Persian scholar and vizier of the Seljuq Empire.
Rising from a lowly position, he was the de facto ruler of the empire for 20 years after the assassination of Alp Arslan in 1072, with an apotheosis as the archetypal "good vizier" of Islamic history.One of his most important legacies was founding schools in cities throughout the Seljuk Empire.
These were called "nezamiyehs" after him.
He wrote Siyasatnama ("Book of Government"), a political treatise that uses historical examples to discuss justice, effective rule, and the role of government in Islamic society.