What is "al-qastallani"

Shihab al-Din Abu'l-Abbas Ahmad ibn Muhammad ibn Abu Bakr al-Qastallani al-Qutaybi al-Shafi'i, also known as ' Al-Qastallani' was a Sunni Islamic scholar who specialized in hadith and theology. He owed his literary fame mainly to his exhaustive commentary on the Sahih al-Bukhari entitled Irshad al-Sari fi Sharh al-Bukhari.