Mufassir and historian, who dedicated his life to collecting and interpreting hadiths. He traversed the length and breadth of the Islamic world, talking with thousands of sheikhs and collecting around 600,000 (!) hadiths. He initially selected 200,000 of them, but filtered most of them out of his book Sahih al-Bukhari, which eventually included only 7275 hadiths, of which 2230 appeared only once. Unsurprisingly, this book became the main collection of hadiths in Islam.