Book Quotes: Shia vs Sunni Beliefs

From My Hope for Peace by Jehan Sadat (page 36-37):

Because of their conviction that leadership of the ummah must remain in the Prophet's own line, Shia Muslims--Shi'at Ali, or Party of Ali--have not recognized the authority of elected Muslim leaders, following instead a line of imams, of which Ali was the first. The Shia imamate, in contrast to the Sunni caliphate, is a religious office as well as a political one. Whereas caliphs regarded their power as temporal, the imams were "divinely inspired, sinless, infallible, religio-political" leaders, according to Akbar Ahmed, author of Islam Today. There are other differences in Sunni and Shiite approaches to Islamic jurisprudence and their interpretations of history that are beyond the scope of this book to explore, but both Sunni and Shiite practice the five pillars of Islam and regard one another as Muslims.