Who is Reza Shah from Daughter of Persia: A Woman's Journey from Her Father's Harem Through the Islamic Revolution and what is their importance?

In February, 1921 a revolt instigated by the British ousted the royal Qajar family, including Satti's father, and made Reza Shah Pavlevi the ruler of Iran. Shazdeh actually gave Reza his start when the future ruler was in Shazdeh's private army. Needing someone to carry a heavy machine gun, Shazdeh promoted tall, hefty, illiterate Reza. When the British were looking for a puppet leader of Iran, they selected Reza from a photograph of officers, apparently because of his imposing height.