On Schacht's Origins of Muhammadan Jurisprudence by Muhammad Mustafa al-Azami [NEW]
A detailed and point-wise refutation of Joseph Schacht's arguments against established Islamic ideal of sunnah and the system of isnaad (chains of narrators). Many hadith rejecters and so-called liberal modernists rest their convictions on his thesis. And it has actually become the bible of Orientalists.