There is consensus of the Ulama that the Saheeh of Imaam Muslim (rahimahullah) and the Saheeh of Imaam Bukhaari (rahimahullah) are the two most authentic kitaabs after the Qur’aan Majeed. From the two, the Saheeh of Imaam Bukhaari (rahimahullah) is regarded as more authentic and holds a higher rank. (Tadreeb-ur-Raawi 1/96)