Al Qawlul Mufeed fee Adillatit Tawheed - English and Arabic

This is one of the books that is recommended by scholars  to study. 

The original, in Arabic, was written by Shaykh Muhammad Ibn Abdul-Wahhaab ibn 'Alee al Yamanee al Wassabee al 'Abdilee.

You can download a copy of the Arabic text here as well.

There is also a wonderful set of 47 lessons on the book that the shaykh gave via telephone conference in 2005/2006.  You can download the lessons in English here, they are in PDF format.

 photo yellow-ruler_zpstf30f6qm.png