Saadi Shīrāzī, better known by his pen name Saadi, also known as Sadi of Shiraz, was a major Persian poet and prose writer of the medieval period. He is recognized for the quality of his writings and for the depth of his social and moral thoughts. Saadi is widely recognized as one of the greatest poets of the classical literary tradition, earning him the nickname "The Master of Speech" or "The Wordsmith" or simply "Master" among Persian scholars. He has been quoted in the Western traditions as well. Bustan has been ranked as one of the 100 greatest books of all time by The Guardian.