encompass all the authentic material; rather, their compilations are confined to sound reports. Even the hadiths they themselves deemed sound and that met their own standards were not all cited in their two books—let alone the authentic reports known to other scholars.

Al-Bukhari said, “I have included in my book only what is sahih, yet I have left out much that is authentic.” Muslim likewise stated, “The hadiths I have set down in this book are sound, but I do not claim that whatever I have left out is weak.”

It follows that their decisions to omit or include a report must have rested on some principle of selection, whether related to degrees of soundness or to other scholarly purposes.

Al-Hakim’s Mustadrak

Al-Hakim Abu ‘Abd Allah al-Naysaburi compiled a work he called al-Mustadrak, intending thereby to supply in this book the authentic reports that al-Bukhari and Muslim had not included.