His special field was LIFE and Charactor of Muhammad Sallallahu Alaihi wasallam and Shaba. He has keenly observed the 23 years of Dawah life of Prophet Sallallahu Alaihi Wasallam.
He has written many books on Seerat/Life of Prophet including
SEERATUN NABI (One of the most famous Seerat book in Urdu)
RAHMAT E ALAM
For rest part of article on Islamic history of Dawah success and failure principle by syed sulaiman nadvi click here http://tablighijamaattruth.blogspot.in/2012/04/islamic-history-of-dawahsuccess-and.html