Sunnah

About the Prophet, sallallaahu `alayhi wa sallam, and his Sunnah - by Imam Abu'l Hasan al-Ash`aree
Declaration About the Sunnah - by Imam Ash-Shaafi`ee
Following the Messenger of Allah is a Must - by Dr. Mustafa as-Siba'i
Indispensability of Hadith - by Dr. Khalid Alvi
The Message of the Prophet's Seerat - by Syed Abul 'Ala Mawdudi