At-Tirmidhi is a significant collection of Hadith, which are the sayings and actions of the Prophet Muhammad. Compiled by the Islamic scholar Abu 'Isa Muhammad ibn 'Isa at-Tirmidhi in the 9th century, it is one of the six major Hadith collections in Sunni Islam. At-Tirmidhi's work is known for its systematic approach, categorizing Hadith based on their authenticity and subject matter. The collection includes over 3,000 Hadith, many of which are unique to At-Tirmidhi. It also features a section on the classification of Hadith, where the author provides insights into the reliability of the narrators. This makes At-Tirmidhi an essential resource for scholars and students of Islamic studies.