A proof that the Qur'an is from God and that Muhammad is a Messenger of God.
Author: The Memphis Dawah Team
Publisher: Memphis Dawah
Source: http://www.islamhouse.com/p/1283
The testimony of "Laa ilaaha ill-Allah", its meaning, prerequisites, conditions, and fruits.
Author: Saleh Bin Fawzaan al-Fawzaan
Publisher: http://www.islammessage.com - Islam Message House Website
Source: http://www.islamhouse.com/p/1223
This book follow the Adadith (prophet sayings) in an attempt to trace their miraculous nature from a scientific perspective so as to pave the Sunnah's way into the hearts of Muslims and non-Muslims as well.
Author: Zaqlol El-Naggar
Publisher: Al-Falah Foundation, Translation, Publication and Distribution
A comprehensive explanation and commentary of the first 24 hadith of Imam al-Nawawi's classic compilation, Riyadh al-Saliheen.
Author: Abu Zakaria Al-Nawawi
The "Islamic Studies" series of books by the prolific writer and scholar Dr. Bilal Philips are part of a meticulously written series intended to guide young Muslims in a manner that helps them acquire a thorough practical and spiritual foundation. This series have been generally acknowledged as an excellent introduction set to the principles of the Islamic faith, with core sciences discussed and explored, for both the new Muslim as well as the "old" Muslim wishing to brush up on the fundamentals.
Author: Abu Ameenah Bilal Philips
A nice discussion of some important points needed by those callling to Islam
Source: http://www.islamhouse.com/p/1243