How to treat Whispers and Doubts in Islam

This a series where I will go through the book 'Tiryaq' of Shaykh Dr. Mutlaq Jaasir of Kuwait. The book is the culmination of a decade of active dawah among atheists by a skilled Mufti and academic. Although there are many doing dawah in this area, very few are so well grounded in Sharia sciences like him. He is an erudite scholar in the traditional sense along with being an academic and he has focused his skillset to this field also. Hence his work is a unique contribution.
Dr. Mutlaq traces the doubts of athiests and/or agnsotics and other Muslims who have lost their way and the 'isms' that have disinformed them and created doubts in them. All these are poisons of the heart and hence the book is called 'Tiryaq' or an antidote.
Alhamdulillah, through his efforts, Allah guided many such lost souls back to Allah and Islam.
After consulting him, it was suggested that I start the reading of the book which would be useful to English speaking audiences/classes, inshaAllah.