Musnad Ishaq Ibn Rahwayh (Arabic: مسند إسحاق بن راهويه), is one of the oldest Hadith book compiled by Imam Ishaq Ibn Rahwayh (d. 853 A.D)., who is the teacher of famous Scholars of Hadiths including Imam Muhammad al-Bukhari, Imam Muslim, Imam Al-Tirmidhi & Imam Al-Nasa'i. Source: Wikipedia (en)