What are the key differences between Sunni and Shia Islam?

Great question! The split originated after the death of Prophet Muhammad in 632 CE over the question of succession. Sunnis accepted Abu Bakr as the first caliph, while Shia Muslims believed leadership should have passed to Ali ibn Abi Talib, the Prophet's cousin and son-in-law. For reliable sources, I'd recommend: - "After the Prophet" by Lesley Hazleton (accessible narrative history) - "The Shia Revival" by Vali Nasr (scholarly but readable) - The Encyclopædia Britannica entries on Sunni and Shia Islam The key theological differences include views on religious authority, the role of imams, and certain ritual practices, though both share the core Five Pillars.

Adding to the above — it's important to note that the differences are often overstated in popular media. Both Sunni and Shia Muslims share the same Quran, believe in the same Prophet, and observe the same Five Pillars. The differences are primarily about historical succession and certain jurisprudential traditions. Pew Research Center has excellent demographic data on the global distribution of Sunni and Shia populations if you're interested in that angle as well.