A great book which explains the real beauty of Islam, by Dr Naji Ibrahim Arfaj.
Author: Naji Ibrahim al-Arfaj
Publisher: http://www.abctruth.net - ABC Truth Website
The Muslim Creed - 'Aqeedatut-Tahaawiyyah.
Author: Abu Jafar at-Tahawi
Translators: Suhaib Hasan AbdulGhaffar
The Three Fundamental Principles and the Four Basic Rules of Islam.
Author: Muhammad Bin Abdul Wahhab
Publisher: Daar Al-Watan
Source: http://www.islamhouse.com/p/1333
This treatise was prepared by the Agency of Islamic Enlightenment in Hajj. Includes a discussion about those things which nullify a person's Islam as well as common errors made by the commonfolk.
Author: Faisal Bin Ali Al-Ba'adani
Reveiwers: Muhammad AbdulRaoof
Publisher: A website Islamic Library www.islamicbook.ws
Introduction to history of polytheism and monotheism: Allah (glory be to him) created all people as Muslims and monotheists but devils came to them and changed and distorted their religion. Allah said in a qudsi hadith, “I created all my slaves as haneefs (monotheists), but the devils came to them, made them deviate from their religion, forbade them that which I had permitted to them, and commanded them to join partners with me for which I has given no authority.” As soon as people commit a type of polytheism, Allah sends his prophets to call them to the suitable type of monotheism.
Author: Ameen Al-Ansaari
Publisher: A website Knowing Allah : http://knowingallah.com
A discussion of the 'pillars' of Eemaan and the factors which invalidate ISlam and remove a person from its fold.
Author: Abdul Aziz bin Abdullah bin Baz
Source: http://www.islamhouse.com/p/1227