Al-Kulayni was a prominent Islamic scholar and hadith compiler from the 9th century. He is best known for his work, Al-Kafi, which is one of the four major hadith collections in Shia Islam. This collection covers various aspects of Islamic teachings, including theology, ethics, and law. Born in Kufa, Iraq, Al-Kulayni dedicated his life to gathering and verifying hadiths, which are sayings and actions of the Prophet Muhammad and the Imams. His meticulous approach has made Al-Kafi a crucial reference for Shia scholars and followers, influencing Islamic thought and practice for centuries.