The following is a link where you can download the english audio files of the explanation of Nizam al-Islam (The System of Islam) by Sheikh Dr. Mohammad Hawarey.
The following is a brief biography of the Sheikh:
He was born in Rabi Thani 1350 H in the family of the Hawarey (disciple) of Prophet Mohammad (saw). The family of Hawarey descends from Az-Zubayr bin Al-Awwam (ra), the son of Saffiyyah the aunt of Rasulullah (saw), Zubayr was known as Al-Hawarey, which means The Disciple. The descendents of this family are spread in Arabian Peninsula and Ash-Sham Lands: Palestine, Syria and Jordan.
The Sheikh holds 1 BA degree in English literature, 1 B.A. degree in Education, 1 MA and 1 PhD in Comparative Religion, and a 2nd PhD in Tafseer. He authored 10 books, amongst which is a Tafseer in 4 volumes.
The shiekh recorded these sessions upon the request of few brothers in the West who considered it more practical to listen than to read. The recording process was carried out using very modest means, in early 1990's.