The author of this treatise is Imam abu Jafar al Tahawi (239 - 321 AH), one of the leading authorities on the Hanafi madhabs.
To illustrate this; his teachers included imam Ismail ibn Yahya Al Muzani (a major student of Imam al shaafi), he collected hadith from Imam an-Nasai (author of Sunan an-Nasai, one of the saheeh Sittah) and his students included.
The period he lived in was the zenith of the dissemination of the Islamic sciences and Imam at Tahawi was one of the giants this era produced.
The author of this treatise is Imam abu Jafar al Tahawi (239 - 321 AH), one of the leading authorities on the Hanafi madhabs