شروط شهادة أن لا إله إلا الله
للشيخ محمد عبد الله مختار محمد
Very good book about the conditions of lâ ilâha illa Allah in 2 volumes.
This book is originally a doctoral thesis presented at the University of Medina and it has received praise from Shaykh 'Ubayd al-Jâbirî.
We find in this book among others:
The meaning of the testimony among the people of the Sunnah and among the people of innovation, the divergence of the scholars concerning the number of conditions (7, 8, 9 or 4), a meticulous explanation of the conditions with their proofs, the words of the scholars on each condition, which contradicts these conditions or what cancel them...