This book is one of the most important Islamic books which gives right answers about Christianity.
Author: Sheikh-ul-Islam ibn Taymiyyah
Islam, is a comprehensive way of Life, does not confine itself to the spiritual aspect of man's life only, rather its primary concern is with the application of its rules to the daily life of man, the author wrote it in an easy and simple method to achieve the very purpose of the book, namely introducing Islam to Muslims and non-Muslims, through the best and simplest way.
Author: Hammodah Abd al-Aati
Publisher: http://www.islamweb.net - Islam Web Website
Brief guide concerning the fundamentals of Islam.
Author: Naasir Bin Abdulkarim al-Aql
Source: http://www.islamhouse.com/p/1295
These are three good books for learning Arabic Language for the non-native speakers. But we should pay your attention that they are for who has slightly good knowledge about Arabic and how to pronounce it. We don't claim that you can consider them as an alternative to a teacher but they are good step for who wants to be excellent at Arabic. With these books, there is an Arabic-English glossary confined to the words mentioned in these books, and the author shows in its introduction how to find any word.
Hajj and Tawheed: Hajj is to set out for Makkah to worship Allah by performing certain religious rights in accordance with the Prophet's (peace and blessings be upon him) Sunnah. It is a time in which to call upon Allah to purify the self from any worship to anyone other than him. This booklet explains the basic rights of Hajj. It also notes that the tawheed of Allah requires the Muslim to follow the perfect way of worship, demonstrated by Muhammad (peace and blessings be upon him) and as understood by the Sahaabah who were the best of mankind.
Author: Dr. Saleh As-Saleh
A Book discussingthe importance of khushoo in prayer and how to achieve it
Author: Imran Hussein
Source: http://www.islamhouse.com/p/1401