This book gives a clear explanation of the Muslim sound Creed which is the core of the religion of Islam, as the belief in Tawhid (monotheism) is the purpose for which Allah created both mankind and jinn, and thus, those whoes belief in Tawhid is corrupt, are not considered Muslims.
Author: Saleh Bin Fawzaan al-Fawzaan
A nice discussion of some important points needed by those callling to Islam
Source: http://www.islamhouse.com/p/1243
Discover Islam: A brief book that guides a person towards Islam, Islam is the religion and way of life of about one Fifth of the world's population. Muslims are of diverse nationalities, cultures and races, but their Religion teaches that all humanity is essentially equal. It guides them to the Straight Path.
Author: Mustafa Malaikah
Reveiwers: Muhammad AbdulRaoof
Publisher: A website Islamic Library www.islamicbook.ws
This book centers around four foundation rules that help explain the meaning of shirk and clarify the many misconceptions that surround the subject.
Author: Muhammad Bin Abdul Wahhab
Reveiwers: Muhammad AbdulRaoof
Translators: Shuwana Abdul-Azeez
Publisher: A website Quran and Sunnah : http://www.qsep.com
This is a brief book which explains the meanings and the definitions of the miracle. It also takes a look at some of the scientific facts mentioned in the Quran which modern scientists, Muslim and non-Muslim alike, affirm as true.
Author: Ahmed Deedat
Issues that the caller to Allah must obtain
Author: Muhammad ibn Saleh al-Othaimeen