Forbis does a good job detailing the beliefs of the average Iranian and why the Shah lost his job. First and Foremost, he summarizes the history of the Iranian monarchy (2,500 years) and the Pahlavi dynasty (50 of those years). The Shah for all his good and bad are detailed here. The assessment of the Shah is fair. He made mistakes and deposited a fortune in his bank account. He also modernized Iran. Of note here, Ayatollah Khomeini rose in revolt when the Shah took over the hugh church estates and gave women the vote in 1963. Forbis takes a look at all aspects of society (religion, women, education, military, agriculture, industrialization) and tells us why the Shah fell. The aftermath is a society that is regressive and still suffers dictatorial rule (by mullahs rather than a Shah).
This is an older book, so for current information you need to go elsewhere. However, this is good book to read to discover Iranian society at the time of the Shah.