What is the best book for studying Tawheed and the Islaamic ‘Aqeedah and how can a person obtain it?
The way of the Messenger in calling non-Muslims to Islam
Proceed with calmness and tranquility up until you enter their land, then invite them to Islaam and inform them of what Allaah the Most High has made obligatory upon them.
The Correct Aqeedah
What is obligatory for a muslim to know in the Aqeedah in order for him to actually be a true Muslim?